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Control and Coordination PYQs – Biology, SSC & Railway

138 Control and Coordination (Biology) questions asked in recent SSC and Railway exams, newest first, with exam, date & shift, answers and solutions.

📚 138 questionsSSC 52 · Railway 86
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SSC Stenographer 2026 – 12 September 2026 Shift 1 · Endocrine glands and hormones

Q1. Which hormone is most directly associated with the regulation of mood and emotional balance?

  1. (a) Adrenaline
  2. (b) Thyroxine
  3. (c) Serotonin
  4. (d) Oxytocin
Answer & solution

Answer: (c) Serotonin

Answer: Option 3 — Serotonin
Serotonin is the chemical messenger that steadies mood, sleep and appetite; low levels are linked with depression and anxiety, which is why it is called the "feel-good" or "happy" hormone.
Adrenaline, thyroxine and oxytocin each have another primary job.
Revision note — Hormones that affect mood and stress
• Serotonin is made from the amino acid tryptophan; about 90 per cent of the body's serotonin is in the gut, the rest in the brain (raphe nuclei).
• Common anti-depressants (SSRIs) work by keeping more serotonin active at the synapse.
• Dopamine — the reward and motivation messenger; its loss in the brain causes Parkinson's disease.
• Melatonin — the sleep hormone from the pineal gland, released in darkness.
• Cortisol — the stress hormone from the adrenal cortex; adrenaline (epinephrine) from the adrenal medulla is the emergency or fight-or-flight hormone that raises heart rate and blood sugar.
• Thyroxine from the thyroid controls the metabolic rate; it needs iodine, and its shortage causes goitre.
• Oxytocin — the "love" or bonding hormone, released by the posterior pituitary; it triggers uterine contractions in childbirth and milk ejection.
• Endorphins are the body's natural pain-killers, released during exercise — the "runner's high".
Do not mix these up
• Serotonin vs dopamine — serotonin steadies mood; dopamine drives reward and pleasure-seeking.
• Adrenaline vs cortisol — both are adrenal stress hormones, but adrenaline (medulla) acts in seconds and cortisol (cortex) in hours.
• Oxytocin vs vasopressin — both come from the posterior pituitary, but vasopressin (ADH) controls water balance, not bonding.
Also asked from this topic: the gland that secretes adrenaline (adrenal gland); the element the thyroid needs to make thyroxine (iodine); the gland that secretes growth hormone (pituitary).
SSC Stenographer 2026 – 11 September 2026 Shift 1 · Hormonal disorders

Q2. A patient is diagnosed with a deficiency of ADH (Antidiuretic Hormone). Which of the following conditions would they most likely exhibit?

  1. (a) High blood sugar levels
  2. (b) Excessive urination and thirst
  3. (c) Excessive pain in bones
  4. (d) Reduced calcium levels in blood
Answer & solution

Answer: (b) Excessive urination and thirst

Answer: Option 2 — Excessive urination and thirst
ADH (vasopressin) makes the kidney tubules reabsorb water back into the blood.
Without it the kidneys pass out large volumes of dilute urine, so the patient urinates constantly and is intensely thirsty — the condition called diabetes insipidus.
Revision note — ADH and the pituitary gland
• ADH, also called vasopressin, is made in the hypothalamus and stored and released by the posterior pituitary.
• It acts on the distal convoluted tubule and the collecting duct of the nephron, raising water reabsorption and concentrating the urine — hence anti-diuretic.
• Its deficiency causes diabetes insipidus: up to 10–20 litres of dilute urine a day with severe thirst, but normal blood sugar.
• The posterior pituitary releases only two hormones — ADH and oxytocin; oxytocin drives uterine contraction and milk ejection.
• The anterior pituitary makes GH, TSH, ACTH, FSH, LH and prolactin; the pituitary as a whole is the master gland, at the base of the brain.
• Alcohol and caffeine suppress ADH, which is why they increase urination.
• For contrast: insulin deficiency gives diabetes mellitus (high blood sugar) and parathormone deficiency gives low blood calcium and tetany.
Do not mix these up
• Diabetes insipidus vs diabetes mellitus — insipidus is a failure of ADH with normal blood sugar; mellitus is a failure of insulin, with high blood sugar and sugar in the urine.
• Anterior vs posterior pituitary — the anterior lobe makes its own hormones; the posterior lobe only stores and releases ADH and oxytocin made in the hypothalamus.
Also asked from this topic: the gland that secretes growth hormone (the pituitary); the condition its deficiency causes in childhood (dwarfism); the source of GH-releasing factor (hypothalamus).
SSC Stenographer 2026 – 9 September 2026 Shift 2 · Brain - parts and functions

Q3. What is the primary function of the grey matter in the human brain?

  1. (a) Regulating heart rate and breathing
  2. (b) Transmitting signals between body and brain
  3. (c) Processing information and decision-making
  4. (d) Producing cerebrospinal fluid
Answer & solution

Answer: (c) Processing information and decision-making

Answer: Option 3 — Processing information and decision-making
Grey matter is made of neuron cell bodies, dendrites and synapses, so this is where the brain actually processes information and takes decisions.
Mere transmission between body and brain is the work of white matter, whose long myelinated axons only carry the signals.
Revision note — The human brain
• Grey matter forms the outer cerebral cortex of the brain and the inner core of the spinal cord; white matter lies inside in the brain and outside in the spinal cord.
• The brain has three parts — the forebrain (cerebrum, thalamus, hypothalamus), the midbrain, and the hindbrain (cerebellum, pons, medulla oblongata).
• The cerebrum is the largest part and the seat of thinking, memory, reasoning and voluntary action, with separate areas for hearing, smell and sight.
• The cerebellum looks after posture, balance and the precision of voluntary movement.
• The medulla runs involuntary acts — heartbeat, breathing, blood pressure, salivation, vomiting.
• The brain is protected by the bony cranium, three membranes called the meninges, and cerebrospinal fluid, which is produced by the choroid plexus in the ventricles.
• An adult human brain weighs about 1.3–1.4 kg and holds roughly 86 billion neurons; the hypothalamus controls hunger, thirst and body temperature.
Do not mix these up
• Grey matter vs white matter — grey matter holds the cell bodies and does the processing; white matter is myelinated axons and does the transmitting.
• Cerebrum vs cerebellum — the cerebrum thinks and decides; the cerebellum balances and coordinates.
• Cerebrum vs medulla — the cerebrum governs voluntary, conscious action; the medulla governs involuntary life processes such as heart rate and breathing.
Also asked from this topic: the part chiefly responsible for thinking (forebrain, the cerebrum, SSC GD 2026); the part with areas for hearing, smell and sight (fore-brain, SSC CHSL 2025); the part regulating salivation and vomiting (medulla, SSC CHSL 2025).
RRB Group D 2025-26 – 21 August 2026 Shift 2 · Spinal cord and reflex action

Q4. Where are reflex arcs primarily formed in the human body?

  1. (a) Heart
  2. (b) Lungs
  3. (c) Brain
  4. (d) Spinal cord
Answer & solution

Answer: (d) Spinal cord

Correct Answer:
Correct Answer: Option 4 – Spinal cord
Explanation:
Reflex arcs are the neural pathways that control reflex actions and are primarily formed in the spinal cord, enabling a rapid response without waiting for the signal to reach and be processed by the brain.
RRB Group D 2025-26 – 21 August 2026 Shift 2 · Plant hormones and tropic movements

Q5. What is the term for the growth of plant roots downward in response to gravity?

  1. (a) Chemotropism
  2. (b) Phototropism
  3. (c) Hydrotropism
  4. (d) Geotropism
Answer & solution

Answer: (d) Geotropism

Correct Answer:
Correct Answer: Option 4 – Geotropism
Explanation:
The directional growth of a plant part in response to gravity is called geotropism (gravitropism). Roots exhibit positive geotropism, growing downward in the direction of the gravitational pull.
RRB Group D 2025-26 – 20 August 2026 Shift 2 · Endocrine glands and hormones

Q6. Which of the following is secreted directly into the blood and carried to different parts of the body?

  1. (a) Saliva
  2. (b) Bile juice
  3. (c) Pancreatic juice
  4. (d) Adrenaline
Answer & solution

Answer: (d) Adrenaline

Correct Answer:
Correct Answer: Option 4 – Adrenaline
Explanation:
Adrenaline is a hormone secreted by the adrenal glands directly into the bloodstream (endocrine secretion), which then carries it to target organs throughout the body.
Important Facts:
• Saliva, bile juice, and pancreatic juice are exocrine secretions released through ducts into the digestive tract, not directly into blood.
RRB Group D 2025-26 – 20 August 2026 Shift 2 · Brain - parts and functions

Q7. Which organ sends messages to muscles to carry out voluntary actions like writing or moving a chair?

  1. (a) Heart
  2. (b) Lungs
  3. (c) Brain
  4. (d) Stomach
Answer & solution

Answer: (c) Brain

Correct Answer:
Correct Answer: Option 3 – Brain
Explanation:
The brain is the main control centre of the nervous system; it sends nerve impulses to skeletal muscles to initiate and control voluntary actions such as writing or moving objects.
Important Facts:
• The cerebrum, the largest part of the brain, is specifically responsible for voluntary actions and thought.
RRB Group D 2025-26 – 20 August 2026 Shift 3 · Plant hormones and tropic movements

Q8. Which of the following environmental stimulus causes roots to grow away from itself?

  1. (a) Gravity
  2. (b) Water
  3. (c) Light
  4. (d) Air
Answer & solution

Answer: (c) Light

Correct Answer:
Option 3 – Light
Explanation:
Roots show negative phototropism — i.e., they grow away from light. (In contrast, roots show positive hydrotropism (grow towards water) and positive geotropism (grow towards/with gravity).)
RRB Group D 2025-26 – 19 August 2026 Shift 1 · Peripheral and autonomic nervous system

Q9. Which type of nerves arise from the brain in humans?

  1. (a) Motor nerves
  2. (b) Cranial nerves
  3. (c) Autonomic nerves
  4. (d) Spinal nerves
Answer & solution

Answer: (b) Cranial nerves

Correct Answer:
Correct Answer: Option 2 – Cranial nerves
Explanation:
Cranial nervesare the 12 pairs of nerves that arise directly from thebrain(mainly the brainstem) and supply the head, neck, and some thoracic/abdominal organs. Spinal nerves, by contrast, arise from the spinal cord.
Important Facts:
• Humans have 12 pairs of cranial nerves and 31 pairs of spinal nerves.
• Examples of cranial nerves: Olfactory, Optic, Vagus, Facial.
• Motor and autonomic nerves are functional classifications, not origin-based.
RRB Group D 2025-26 – 19 August 2026 Shift 3 · Plant hormones and tropic movements

Q10. Which mechanism allows the sensitive plant to move its leaves immediately after being touched?

  1. (a) Electrical impulses in muscle tissue
  2. (b) Use of animal-like proteins
  3. (c) Changing the amount of water in certain cells
  4. (d) Specialized nervous tissue
Answer & solution

Answer: (c) Changing the amount of water in certain cells

Correct Answer:
Option 3 – Changing the amount of water in certain cells
Explanation:
The sensitive plant (Mimosa pudica, touch-me-not) shows rapid leaf movement upon touch due to a sudden change in thewater content (turgor pressure)of specialized cells called the pulvinus, located at the base of the leaflets. This is not due to nerves or muscles, since plants lack a nervous system.
Important Facts:
• This response is an example of 'seismonasty' or 'thigmonasty' — a non-directional response to touch.
• Plants respond to stimuli via hormones and turgor changes, not nerve impulses.
Correct Answer: Option 3 – Changing the amount of water in certain cells
RRB Group D 2025-26 – 18 August 2026 Shift 2 · Spinal cord and reflex action

Q11. Why is consciously thinking before withdrawing the hand from a hot object considered inefficient?

  1. (a) The brain cannot receive incoming sensory signals sent directly from the skin.
  2. (b) Muscles cannot respond to signals sent by the brain during dangerous events.
  3. (c) Nerve impulses travel only from the body muscles directly back to the brain.
  4. (d) Thinking involves time taking complex interactions of many nerve impulses.
Answer & solution

Answer: (d) Thinking involves time taking complex interactions of many nerve impulses.

Reflex Action vs Conscious Thought
Withdrawing the hand from a hot object is areflex action— controlled by the spinal cord, bypassing conscious brain processing for a rapid protective response.
Consciously thinking about the response would require the sensory signal to travel to the brain, be processed through complex neural pathways, and a motor signal to travel back — a much slower, time-consuming process compared to a direct reflex arc, making it inefficient/dangerous in urgent situations.
Correct Answer: Thinking involves time taking complex interactions of many nerve impulses.
RRB Group D 2025-26 – 17 August 2026 Shift 1 · Brain - parts and functions

Q12. Salivation when seeing food is an example of which type of action?

  1. (a) Self-propagated
  2. (b) Planned
  3. (c) Voluntary
  4. (d) Involuntary
Answer & solution

Answer: (d) Involuntary

Salivation as a Reflex Action
Salivation on seeing/smelling food is an automatic, unconscious response controlled by the autonomic nervous system — it happens without conscious thought or decision-making. This makes it aninvoluntary action(a reflex response), similar to a conditioned reflex.
Correct Answer: Involuntary
RRB Group D 2025-26 – 17 August 2026 Shift 2 · Plant hormones and tropic movements

Q13. In what way does geotropism support effective rooting in plants?

  1. (a) It directs photosynthetic tissues into the soil.
  2. (b) It makes roots grow toward sunlight.
  3. (c) It directs roots to grow downward, anchoring the plant and helping them access moisture and nutrients.
  4. (d) It prevents roots from branching.
Answer & solution

Answer: (c) It directs roots to grow downward, anchoring the plant and helping them access moisture and nutrients.

Geotropism in Roots
Geotropism (gravitropism) is the growth response of plant parts to gravity. Roots show positive geotropism — they growdownward into the soil, which anchors the plant firmly and allows the root system to access water and nutrients from deeper soil layers.
• Roots are non-photosynthetic and do not grow toward sunlight (that is phototropism, shown by shoots).
• Geotropism does not prevent branching of roots.
Correct Answer: It directs roots to grow downward, anchoring the plant and helping them access moisture and nutrients.
RRB Group D 2025-26 – 14 August 2026 Shift 1 · Plant hormones and tropic movements

Q14. What does the fact that movement in a plant occurs away from the point of touch suggest about plant coordination?

  1. (a) Photosynthesis
  2. (b) Growth stimulation
  3. (c) Water absorption
  4. (d) Signal transmission
Answer & solution

Answer: (d) Signal transmission

Answer: Option 4 – Signal transmission.
• Movement away from touch shows the planttransmits a signal(stimulus response) between cells.
RRB Group D 2025-26 – 14 August 2026 Shift 3 · Neuron and nerve impulse

Q15. Which part of a neuron receives information from the environment?

  1. (a) Dendrite
  2. (b) Axon
  3. (c) Nucleus
  4. (d) Synapse
Answer & solution

Answer: (a) Dendrite

Answer: Option 1 – Dendrite.
•Dendritesreceive impulses/information at a neuron.
RRB Group D 2025-26 – 13 August 2026 Shift 1 · Plant hormones and tropic movements

Q16. In geotropism, what does gravity act as?

  1. (a) Directional stimulus
  2. (b) Reversible signal
  3. (c) Internal factor
  4. (d) Biotic factor
Answer & solution

Answer: (a) Directional stimulus

Answer: Option 1 – Directional stimulus.
• In geotropism, gravity acts as adirectional stimulusguiding growth.
RRB Group D 2025-26 – 12 August 2026 Shift 1 · Neuron and nerve impulse

Q17. Why is the structure of neurons important for their role in the nervous system?

  1. (a) To produce enzymes
  2. (b) To store nutrients
  3. (c) Repairs tissues
  4. (d) Allows signal transmission
Answer & solution

Answer: (d) Allows signal transmission

Answer: Option 4 – Allows signal transmission.
• A neuron's long structure (dendrites, axon) is suited totransmitting electrical impulses.
RRB Group D 2025-26 – 12 August 2026 Shift 3 · Plant hormones and tropic movements

Q18. Which factor does NOT contribute to immediate plant movement after a stimulus?

  1. (a) Water flow
  2. (b) Shape change
  3. (c) Muscle contraction
  4. (d) Signal transfer
Answer & solution

Answer: (c) Muscle contraction

Answer: Option 3 – Muscle contraction.
• Plants have no muscles; immediate movement comes fromwater flow, shape change and signal transfer, not muscle contraction.
RRB Group D 2025-26 – 12 August 2026 Shift 3 · Plant hormones and tropic movements

Q19. Which statement correctly compares information conduction in plants and animals?

  1. (a) Plants lack specialized tissue
  2. (b) Plants use nerves
  3. (c) Animals lack conduction
  4. (d) Both use same tissue
Answer & solution

Answer: (a) Plants lack specialized tissue

Answer: Option 1 – Plants lack specialized tissue.
• Plants haveno nervous tissue; they use chemical/electrical signals, unlike animals' specialised nerves.
RRB Group D 2025-26 – 11 August 2026 Shift 2 · Plant hormones and tropic movements

Q20. What causes plant cells to change shape during movement?

  1. (a) Special proteins
  2. (b) Light energy
  3. (c) Temperature
  4. (d) Water content
Answer & solution

Answer: (d) Water content

Answer: Option 4 – Water content.
• Changes inwater content (turgor pressure)in plant cells cause them to swell or shrink, producing movement.
RRB Group D 2025-26 – 10 August 2026 Shift 1 · Plant hormones and tropic movements

Q21. Which environmental factor causes a plant shoot to bend toward a window?

  1. (a) Water
  2. (b) Gravity
  3. (c) Light
  4. (d) Temperature
Answer & solution

Answer: (c) Light

Answer: Option 3 — Light
A shoot bending toward a window showsphototropism— growth towardlight→ Option 3.
RRB Group D 2025-26 – 10 August 2026 Shift 2 · Peripheral and autonomic nervous system

Q22. Which of the following structures connect the brain to the muscles?

  1. (a) Bones
  2. (b) Blood
  3. (c) Glands
  4. (d) Nerves
Answer & solution

Answer: (d) Nerves

Answer: Option 4 – Nerves.
•Nervescarry impulses between the brain/spinal cord and the muscles, coordinating movement.
RRB Group D 2025-26 – 10 August 2026 Shift 2 · Brain - parts and functions

Q23. Which part of the human brain is responsible for most thinking activities?

  1. (a) Hind-brain
  2. (b) Cerebellum
  3. (c) Fore-brain
  4. (d) Mid-brain
Answer & solution

Answer: (c) Fore-brain

Answer: Option 3 – Fore-brain.
• Thefore-brain (cerebrum)is the main thinking part – it controls voluntary actions, reasoning, memory and intelligence.
RRB Group D 2025-26 – 9 August 2026 Shift 2 · Endocrine glands and hormones

Q24. Which hormone controls the blood sugar level in the body?

  1. (a) Thyroid hormone
  2. (b) Adrenaline
  3. (c) Growth hormone
  4. (d) Insulin
Answer & solution

Answer: (d) Insulin

Answer: Option 4 — Insulin
Insulincontrols blood sugar → Option 4.
RRB Group D 2025-26 – 6 August 2026 Shift 1 · Neuron and nerve impulse

Q25. After the dendrite receives information, what is the next structure the impulse moves to?

  1. (a) Cell body
  2. (b) Axon end
  3. (c) Dendrite
  4. (d) Axon
Answer & solution

Answer: (a) Cell body

Answer: Option 1 — Cell body
Impulse path: dendrite →cell body→ axon → axon terminal → Option 1.
RRB Group D 2025-26 – 6 August 2026 Shift 2 · Neuron and nerve impulse

Q26. Which is the first part of a neuron to receive information?

  1. (a) Cell body
  2. (b) Dendrite
  3. (c) Axon terminal
  4. (d) Axon
Answer & solution

Answer: (b) Dendrite

Answer: Option 2 — Dendrite
Thedendriteis the first part of a neuron to receive information → Option 2.
RRB Group D 2025-26 – 6 August 2026 Shift 3 · Plant hormones and tropic movements

Q27. What movement in plants causes a tendril to circle and cling to an object?

  1. (a) Nastic movement
  2. (b) Tropic movement
  3. (c) Locomotary movement
  4. (d) Turgor movement
Answer & solution

Answer: (b) Tropic movement

Answer: Option 2 — Tropic movement
A tendril coiling around support is a directional growth response =tropic (thigmotropic) movement→ Option 2.
RRB Group D 2025-26 – 6 August 2026 Shift 3 · Endocrine glands and hormones

Q28. Which organ produces hormones that regulate the menstrual cycle?

  1. (a) Testes
  2. (b) Ovaries
  3. (c) Thyroid
  4. (d) Pancreas
Answer & solution

Answer: (b) Ovaries

Answer: Option 2 — Ovaries
Theovariesproduce hormones (oestrogen, progesterone) that regulate the menstrual cycle → Option 2.
RRB Group D 2025-26 – 5 August 2026 Shift 1 · Neuron and nerve impulse

Q29. The specialised signal that travels along a nerve fibre to communicate with other cells is specifically known as a(n) __________.

  1. (a) Axon
  2. (b) Nerve impulse
  3. (c) Stimulus
  4. (d) Hormone
Answer & solution

Answer: (b) Nerve impulse

Answer: Option 2 — Nerve impulse
The signal travelling along a nerve fibre is thenerve impulse→ Option 2.
RRB Group D 2025-26 – 5 August 2026 Shift 1 · Plant hormones and tropic movements

Q30. What happens when the leaves of the touch-me-not (Mimosa) plant are touched?

  1. (a) They produce flowers
  2. (b) They grow larger
  3. (c) They fold up and droop
  4. (d) They change color
Answer & solution

Answer: (c) They fold up and droop

Answer: Option 3 — They fold up and droop
The touch-me-not (Mimosa) shows thigmonasty: leavesfold and droopon touch → Option 3.
RRB Group D 2025-26 – 4 August 2026 Shift 1 · Spinal cord and reflex action

Q31. A child presents with a congenital absence of the vertebral column. Which major body system would be primarily compromised?

  1. (a) Central nervous system protection
  2. (b) Respiratory gas exchange
  3. (c) Cutaneous respiration
  4. (d) External digestion
Answer & solution

Answer: (a) Central nervous system protection

Answer: Option 1 — Central nervous system protection
Thevertebral column protects the spinal cord(part of the CNS). Its absence chiefly compromisesCNS protection→ Option 1.
RRB Group D 2025-26 – 4 August 2026 Shift 1 · Neuron and nerve impulse

Q32. Which part of a neuron carries nerve impulses away from the cell body?

  1. (a) Root hair
  2. (b) Cilia
  3. (c) Axon
  4. (d) Flagellum
Answer & solution

Answer: (c) Axon

Answer: Option 3 — Axon
Theaxoncarries impulsesawayfrom the cell body → Option 3.
RRB Group D 2025-26 – 4 August 2026 Shift 2 · Plant hormones and tropic movements

Q33. Which type of plant movement is caused by growth in response to a stimulus?

  1. (a) Circular growth
  2. (b) Rapid contraction
  3. (c) Random growth
  4. (d) Directional growth
Answer & solution

Answer: (d) Directional growth

Answer: Option 4 — Directional growth
Growth movement toward/away from a stimulus is atropism = directional growth→ Option 4.
RRB Group D 2025-26 – 3 August 2026 Shift 1 · Neuron and nerve impulse

Q34. In a neuron, what are the short, branched fibres that receive impulses from other neurons called?

  1. (a) Axons
  2. (b) Muscle fibres
  3. (c) Dendrites
  4. (d) Cartilage discs
Answer & solution

Answer: (c) Dendrites

Answer: Option 3 — Dendrites
Concept:In a neuron, the short, branched fibres thatreceiveimpulses from other neurons are thedendrites. The long fibre that carries the impulse away is the axon → Option 3.
RRB Group D 2025-26 – 3 August 2026 Shift 2 · Brain - parts and functions

Q35. Which part of the human brain is mainly involved in maintaining body balance?

  1. (a) Pons
  2. (b) Cerebrum
  3. (c) Medulla
  4. (d) Cerebellum
Answer & solution

Answer: (d) Cerebellum

Answer: Option 4 — Cerebellum
Thecerebellumcontrolsbalance, posture and coordinationof voluntary movements → Option 4. (Cerebrum = thinking; medulla = involuntary actions like heartbeat.)
RRB NTPC UG CBT-1 2025-26 – 19 June 2026 Shift 3 · Brain - parts and functions

Q36. Which function is primarily regulated by the medulla?

  1. (a) Vision
  2. (b) Thinking
  3. (c) Involuntary actions
  4. (d) Memory
Answer & solution

Answer: (c) Involuntary actions

Topic: Medulla Oblongata (Brain Stem)
The medulla is part of the hindbrain located at the base of the brain.
Primary Functions:
Controls involuntary actions like heartbeat, breathing, blood pressure, swallowing, and vomiting.
Vision → Occipital lobe
Thinking → Cerebrum
Memory → Hippocampus
Answer: Option 3 → Involuntary actions
RRB NTPC UG CBT-1 2025-26 – 17 June 2026 Shift 1 · Hormonal disorders

Q37. Which of the following is a common symptom of diabetes mellitus?

  1. (a) Increased hair growth
  2. (b) Loss of hearing
  3. (c) Decreased thirst
  4. (d) Frequent urination
Answer & solution

Answer: (d) Frequent urination

Topic:Diabetes Mellitus Symptoms
High blood glucose → kidneys filter excess sugar
Excess glucose pulls water →polyuria (frequent urination)
Classic triad: Polyuria, Polydipsia (increased thirst), Polyphagia
Other options incorrect:
Hair growth, hearing loss, decreased thirst are NOT diabetes symptoms
Answer: Option 4 → Frequent urination
SSC GD 2026 – 30 May 2026 Shift 2 · Hormonal disorders

Q38. Deficiency of insulin in the body can lead to __________.

  1. (a) Goitre
  2. (b) Diabetes
  3. (c) Dwarfism
  4. (d) Hypertension
Answer & solution

Answer: (b) Diabetes

Correct Answer: Diabetes (Option 2)
Insulin is a hormone secreted by the beta cells of the islets of Langerhans in the pancreas. Its deficiency (or the body's inability to use it effectively) results in Diabetes Mellitus, a condition where blood glucose levels remain elevated (hyperglycaemia). Type 1 diabetes is caused by destruction of beta cells leading to insulin deficiency.
Why others are wrong:
- Goitre: Caused by iodine deficiency, leading to enlargement of the thyroid gland.
- Dwarfism: Caused by deficiency of growth hormone (somatotropin) secreted by the pituitary gland.
- Hypertension: High blood pressure; not caused by insulin deficiency.
SSC GD 2026 – 29 May 2026 Shift 2 · Endocrine glands and hormones

Q39. Hormones like adrenaline are associated with which body system?

  1. (a) Nervous system
  2. (b) Endocrine system
  3. (c) Digestive system
  4. (d) Circulatory system
Answer & solution

Answer: (b) Endocrine system

Correct Answer: Endocrine system — Option (b)
Hormones like adrenaline (epinephrine) are associated with the Endocrine system. About the Endocrine System: Definition: The endocrine system is a network of glands and organs that produce, store, and secrete hormones directly into the bloodstream; Key feature: Ductless glands — hormones are secreted directly into the blood (no ducts, unlike exocrine glands); About Adrenaline: Chemical name: Epinephrine; Produced by: Adrenal medulla (inner part of the adrenal glands, located above the kidneys); Function: Fight-or-flight hormone — released during stress, fear, or excitement; Effects: Increased heart rate, dilated pupils, increased blood sugar, enhanced muscle strength, reduced digestion; Part of the catecholamine group; About major Endocrine Glands and their hormones: Pituitary gland (master gland): Growth hormone (GH), TSH, ACTH, FSH, LH, ADH, Oxytocin; Thyroid gland: Thyroxine (T4), Triiodothyronine (T3) — regulate metabolism; Parathyroid glands: Parathyroid hormone (PTH) — regulates calcium; Adrenal glands: Adrenal cortex: Cortisol, Aldosterone; Adrenal medulla: Adrenaline (epinephrine), Noradrenaline (norepinephrine); Pancreas: Insulin, Glucagon — regulate blood sugar; Gonads: Testosterone (testes), Estrogen, Progesterone (ovaries); Pineal gland: Melatonin — regulates sleep; Thymus: Thymosin — immune function; Difference from Nervous System: Nervous system uses electrical signals (nerve impulses); Endocrine system uses chemical signals (hormones) through blood; Nervous system is fast, hormonal regulation is slower but longer-lasting.
Option (a) Nervous system — Incorrect: Adrenaline is NOT associated with the nervous system; while adrenaline affects the nervous system (it acts on adrenergic receptors in the sympathetic nervous system), it is a HORMONE produced by the adrenal medulla (an endocrine gland); hormones are chemical messengers of the endocrine system, not the nervous system; although the adrenal medulla is also part of the sympathetic nervous system in terms of innervation, functionally adrenaline is a hormone of the endocrine system.
Option (c) Digestive system — Incorrect: Adrenaline is NOT associated with the digestive system; the digestive system involves organs like the stomach, small intestine, large intestine, liver, pancreas (exocrine function), and accessory organs; while the digestive system does produce some hormones (gastrin, secretin, cholecystokinin), adrenaline is not one of them; adrenaline is produced by the adrenal medulla as part of the endocrine system.
Option (d) Circulatory system — Incorrect: Adrenaline is NOT associated with the circulatory system (heart and blood vessels); the circulatory system transports hormones like adrenaline through the blood, but it does NOT produce them; adrenaline is produced by the adrenal glands (endocrine system); although adrenaline significantly affects the circulatory system (increasing heart rate, blood pressure), it belongs to the endocrine system.
SSC GD 2026 – 29 May 2026 Shift 3 · Spinal cord and reflex action

Q40. The spinal cord is protected by:

  1. (a) Ribs
  2. (b) Vertebral column
  3. (c) Cerebellum
  4. (d) Pons
Answer & solution

Answer: (b) Vertebral column

Correct Answer: Vertebral column — Option (b)
The spinal cord is protected by the Vertebral column (backbone/spine). About the Vertebral Column: Also known as: Backbone, Spine, Spinal column; Structure: Made up of 33 individual bones called vertebrae; Vertebral formula in humans: Cervical (neck) — 7 vertebrae (C1-C7); Thoracic (chest) — 12 vertebrae (T1-T12); Lumbar (lower back) — 5 vertebrae (L1-L5); Sacral — 5 fused vertebrae = sacrum; Coccygeal — 4 fused vertebrae = coccyx (tailbone); Total: 33 bones (26 in adults as sacral and coccygeal fuse); Protection of spinal cord: The vertebrae form a bony tunnel called the vertebral canal (spinal canal); The spinal cord runs through this canal; The bony vertebrae protect the delicate spinal cord from injury; Additional protection by: Meninges (three membranes: dura mater, arachnoid mater, pia mater); Cerebrospinal fluid (CSF) — acts as shock absorber; About the spinal cord: Part of the Central Nervous System (CNS); Extends from the brainstem (medulla oblongata) down to L1-L2 vertebral level (in adults); Functions: Conducts nerve signals between brain and body; Controls reflex actions; Contains 31 pairs of spinal nerves; About brain protection: Brain is protected by the skull (cranium); NOT by the vertebral column; About ribs: Ribs protect the heart and lungs (thoracic organs); NOT the spinal cord; About cerebellum and pons: These are PARTS OF THE BRAIN — they are brain structures, not protective structures; Cerebellum: Controls balance, coordination; Pons: Controls breathing, sleep, swallowing.
Option (a) Ribs — Incorrect: Ribs do NOT protect the spinal cord; ribs protect the organs of the thoracic cavity — specifically the heart and lungs; the spinal cord is protected by the vertebral column (backbone); while some thoracic vertebrae do articulate with ribs, the ribs themselves are not the protective structure for the spinal cord.
Option (c) Cerebellum — Incorrect: The cerebellum is NOT a protective structure for the spinal cord; it is a PART OF THE BRAIN located in the posterior cranial fossa; the cerebellum is responsible for coordination of movement, balance, and fine motor control; it is itself protected by the skull; the spinal cord is protected by the vertebral column. The candidate incorrectly selected this option.
Option (d) Pons — Incorrect: The Pons is NOT a protective structure for the spinal cord; it is a PART OF THE BRAINSTEM located between the medulla oblongata and the midbrain; the pons is involved in breathing, sleeping, swallowing, bladder control, hearing, equilibrium, taste, and eye movement; it is itself protected by the skull; the spinal cord is protected by the vertebral column.
SSC GD 2026 – 26 May 2026 Shift 2 · Plant hormones and tropic movements

Q41. Which hormone inhibits plant growth and can cause wilting of leaves?

  1. (a) Cytokinin
  2. (b) Gibberellin
  3. (c) Abscisic Acid
  4. (d) Auxin
Answer & solution

Answer: (c) Abscisic Acid

Correct Answer: Abscisic Acid — Option (c)
Abscisic Acid (ABA) is the plant hormone that inhibits plant growth and can cause wilting of leaves. About Abscisic Acid (ABA): Chemical nature: A sesquiterpenoid (15-carbon compound); Synthesized in: Leaves, roots, fruits, and seeds; Also called: The 'Stress Hormone' of plants because it helps plants respond to environmental stresses; Functions of Abscisic Acid: Growth inhibition: ABA inhibits cell elongation and division — it is an INHIBITOR (unlike other hormones); Stomatal closure: During water stress/drought, ABA causes stomatal guard cells to close, reducing water loss — BUT if closure is extreme, leaves may wilt; Leaf senescence and abscission: ABA promotes aging and falling of leaves; Seed dormancy: Maintains seeds in dormant state — prevents premature germination; Bud dormancy: Induces winter dormancy in buds; Fruit ripening: Involved in fruit maturation; ABA and wilting: ABA causes stomata to close to conserve water; In severe drought, ABA levels rise dramatically, causing extreme stomatal closure and ultimately leaf wilting; ABA and seed germination: ABA inhibits germination — this is antagonized by Gibberellins; About other plant hormones: Auxin (IAA): Promotes cell elongation, phototropism, geotropism, apical dominance; Gibberellins: Promote stem elongation, seed germination, flowering; Cytokinin: Promotes cell division (cytokinesis), delays leaf senescence, promotes lateral bud growth; Ethylene: Promotes fruit ripening, leaf/flower abscission.
Option (a) Cytokinin — Incorrect: Cytokinin is a plant growth PROMOTER — it promotes cell division (cytokinesis), promotes lateral bud growth, delays leaf senescence (aging and yellowing), and promotes chlorophyll synthesis; cytokinins do NOT inhibit growth or cause wilting. The candidate selected this incorrect option.
Option (b) Gibberellin — Incorrect: Gibberellins are plant growth PROMOTERS — they promote stem elongation (internode elongation), seed germination, bolting (flowering in biennials), and fruit development; they do NOT inhibit growth or cause wilting.
Option (d) Auxin — Incorrect: Auxin (IAA — Indole-3-acetic acid) is a plant growth PROMOTER that promotes cell elongation, phototropism (bending toward light), geotropism, apical dominance, and root formation; auxin does NOT inhibit growth or cause wilting; the correct answer is Abscisic Acid.
SSC GD 2026 – 25 May 2026 Shift 1 · Brain - parts and functions

Q42. Which part of the brain is mainly responsible for thinking?

  1. (a) Midbrain
  2. (b) Forebrain
  3. (c) Hindbrain
  4. (d) Spinal cord
Answer & solution

Answer: (b) Forebrain

Correct Answer: Forebrain — Option (b)
The Forebrain ( अग्रमस्तिष्क ) is mainly responsible for thinking and other higher cognitive functions. About the human brain structure: The brain is divided into three main regions: Forebrain (Prosencephalon/Anterior Brain): Largest part of the brain; Contains the Cerebrum (largest part), Thalamus, Hypothalamus, and Limbic system; Cerebral cortex (outer layer of cerebrum): Responsible for thinking, reasoning, memory, consciousness, language, decision-making, and voluntary actions; The forebrain controls all higher mental functions; Midbrain (Mesencephalon): Connects forebrain and hindbrain; Involved in visual and auditory reflexes, eye movement, arousal; Hindbrain (Rhombencephalon): Contains the Cerebellum (balance and coordination), Pons (relay station, breathing regulation), and Medulla Oblongata (controls involuntary functions — breathing, heart rate, blood pressure); Spinal Cord: Not part of the brain; it is part of the central nervous system below the brain; Conducts nerve impulses between brain and body; Controls reflex actions; Key functions of Forebrain: Thinking, reasoning, and problem-solving (cerebral cortex); Memory (hippocampus — part of limbic system); Emotions (amygdala — limbic system); Language processing (Broca's area, Wernicke's area); Sensory processing; Voluntary movement control (motor cortex).
Option (a) Midbrain — Incorrect: The Midbrain (Mesencephalon) is primarily involved in processing visual and auditory reflexes, controlling eye movements, and maintaining arousal — it is NOT mainly responsible for thinking; the Forebrain/Cerebrum handles thinking. The candidate selected this incorrect option.
Option (c) Hindbrain — Incorrect: The Hindbrain (containing cerebellum, pons, and medulla) controls balance, coordination, breathing, and involuntary functions — NOT primarily responsible for thinking; thinking is a function of the Forebrain (cerebral cortex).
Option (d) Spinal cord — Incorrect: The Spinal cord is part of the central nervous system but is NOT a part of the brain — it mainly conducts nerve impulses and controls reflex actions; thinking is exclusively a function of the brain's Forebrain (cerebral cortex).
SSC GD 2026 – 25 May 2026 Shift 3 · Brain - parts and functions

Q43. Which of the following is an example of an involuntary action in humans?

  1. (a) Writing
  2. (b) Rocking a chair
  3. (c) Talking
  4. (d) Vomiting
Answer & solution

Answer: (d) Vomiting

Correct Answer: Vomiting — Option (d)
Vomiting ( वमन ) is an example of an involuntary action in humans. About Voluntary vs Involuntary Actions: Voluntary actions: Actions that are performed consciously and under the control of the will (cerebrum); Controlled by the somatic nervous system; Examples: Writing, walking, talking, rocking a chair, eating, etc.; Involuntary actions: Actions that occur WITHOUT conscious control; Controlled by the autonomic nervous system (ANS) and mediated by brain centers other than the cerebrum; Examples: Heartbeat, breathing, digestion, blinking, sneezing, coughing, vomiting, sweating, etc.; About Vomiting as an Involuntary Action: Vomiting is controlled by the vomiting center located in the medulla oblongata of the brainstem; It is a reflex action — the brain triggers the vomiting reflex in response to stimuli (nauseating substances, inner ear disturbances, motion sickness); It cannot be completely controlled by conscious will; The diaphragm and abdominal muscles contract involuntarily during vomiting; Reflex actions (another category of involuntary actions): Knee-jerk reflex, withdrawal reflex (pulling hand from hot object), pupillary reflex; These are controlled by the spinal cord without involving the brain; Autonomic functions (involuntary): Heartbeat (cardiac muscle contractions), peristalsis (digestive movements), hormone secretion.
Option (a) Writing — Incorrect: Writing is a highly coordinated VOLUNTARY action — it requires conscious thought, fine motor control, and deliberate movement; it is controlled by the motor cortex (cerebrum) and is entirely under conscious will; it is NOT an involuntary action.
Option (b) Rocking a chair — Incorrect: Rocking a chair is a VOLUNTARY action — it requires conscious decision and deliberate muscle movements to initiate and maintain; it is under full conscious control and cannot be classified as involuntary.
Option (c) Talking — Incorrect: Talking (speech) is a VOLUNTARY action — it involves conscious coordination of the speech areas (Broca's area) and respiratory muscles; while breathing is involuntary, the act of forming words and speaking is a deliberate voluntary action under conscious control.
SSC GD 2026 – 19 May 2026 Shift 3 · Endocrine glands and hormones

Q44. Which of the following endocrine glands in males secretes hormones related to puberty?

  1. (a) Pineal gland
  2. (b) Testes
  3. (c) Pancreas
  4. (d) Thymus gland
Answer & solution

Answer: (b) Testes

Correct Answer: Testes — Option (b)
The testes (male gonads) are the primary endocrine glands in males that secrete hormones responsible for puberty. The main hormone secreted by the testes is Testosterone (an androgen), which triggers puberty in males and causes the development of secondary sexual characteristics such as: growth of facial and body hair, deepening of the voice (voice changes), enlargement of the larynx (Adam's apple), increase in muscle mass and bone density, enlargement of the testes and penis, development of sperm production (spermatogenesis), and increased height. The secretion of testosterone is regulated by LH (Luteinizing Hormone) from the pituitary gland, which is in turn controlled by GnRH from the hypothalamus.
Option (a) Pineal gland — Incorrect: The pineal gland secretes melatonin, which regulates the sleep-wake cycle (circadian rhythms) and seasonal biological functions; it does not secrete the primary puberty hormones in males.
Option (c) Pancreas — Incorrect: The pancreas secretes insulin and glucagon for blood sugar regulation; it does not secrete hormones responsible for male puberty.
Option (d) Thymus gland — Incorrect: The thymus gland secretes thymosin and other thymic hormones that help develop the immune system (T-lymphocytes); it is not responsible for male puberty hormones.
SSC GD 2026 – 9 May 2026 Shift 2 · Endocrine glands and hormones

Q45. Which brain structure is responsible for releasing the growth hormone-releasing factor in humans?

  1. (a) Hypothalamus
  2. (b) Thyroid gland
  3. (c) Pituitary gland
  4. (d) Thymus gland
Answer & solution

Answer: (a) Hypothalamus

Correct Answer: Hypothalamus — Option (a)
The Hypothalamus is the brain structure responsible for releasing Growth Hormone-Releasing Hormone (GHRH), also called Growth Hormone-Releasing Factor (GRF or GHRF). The hypothalamus acts as the master regulator of the endocrine system — it secretes GHRH which travels through the hypophyseal portal system to the anterior pituitary gland, stimulating it to secrete Growth Hormone (GH/Somatotropin). GH then acts on various tissues and organs — promoting protein synthesis, bone growth, and fat metabolism. The hypothalamus also produces GHIH (Growth Hormone-Inhibiting Hormone/Somatostatin) to inhibit GH release.
Option (b) Thyroid gland — Incorrect: The thyroid gland secretes thyroxine (T4) and triiodothyronine (T3); it does not release growth hormone-releasing factor.
Option (c) Pituitary gland — Incorrect: The pituitary gland SECRETES Growth Hormone (GH) in response to GHRH from the hypothalamus — it does not release the releasing factor itself.
Option (d) Thymus gland — Incorrect: The thymus gland (located in the chest) is part of the immune system and produces thymosin hormones for T-cell development; it has no role in growth hormone regulation.
RRB NTPC UG CBT-1 2025-26 – 9 May 2026 Shift 1 · Endocrine glands and hormones

Q46. Which pancreatic hormone regulates blood glucose levels by stimulating the uptake of glucose by body cells?

  1. (a) Cortisol
  2. (b) Glucagon
  3. (c) Thyroxine
  4. (d) Insulin
Answer & solution

Answer: (d) Insulin

Topic:Pancreatic Hormones and Blood Glucose Regulation
Insulinis secreted by beta cells of pancreas.
Function: Lowers blood glucose by promoting glucose uptake into cells.
Converts excess glucose to glycogen (stored in liver and muscles).
Glucagonhas opposite effect - raises blood glucose.
Answer: Option 4 → Insulin
SSC GD 2026 – 8 May 2026 Shift 1 · Brain - parts and functions

Q47. Which of the following is an example of voluntary action seen in humans?

  1. (a) Vomiting
  2. (b) Salivation
  3. (c) Writing
  4. (d) Breathing
Answer & solution

Answer: (c) Writing

Correct Answer: Writing — Option (c)
Writing is a voluntary action — it is consciously initiated and controlled by the cerebral cortex (somatic nervous system). Voluntary actions require conscious thought and deliberate effort. In contrast: Vomiting is a reflex action (though it can sometimes be consciously suppressed, it is triggered by the vomiting centre in the medulla oblongata); Salivation is primarily an involuntary reflex controlled by the autonomic nervous system (though it can be triggered by thought of food); Breathing is predominantly involuntary (controlled by the respiratory centre in the brainstem) though it can be temporarily brought under voluntary control.
Option (a) Vomiting — Incorrect: Vomiting is primarily an involuntary reflex action coordinated by the vomiting centre in the medulla oblongata of the brain stem.
Option (b) Salivation — Incorrect: Salivation is an involuntary reflex action controlled by the autonomic nervous system in response to food stimuli.
Option (d) Breathing — Incorrect: Breathing is primarily an involuntary action regulated by the respiratory centre in the medulla oblongata, though it can temporarily be brought under voluntary control.
RRB NTPC UG CBT-1 2025-26 – 7 May 2026 Shift 3 · Brain - parts and functions

Q48. Which part of the musculoskeletal system is primarily responsible for protecting the brain?

  1. (a) Spine
  2. (b) Pelvic girdle
  3. (c) Rib cage
  4. (d) Skull
Answer & solution

Answer: (d) Skull

Topic:Musculoskeletal System - Protective Functions
Skull (Cranium)- Bony structure encasing the brain.
Protects brain from external injuries and impacts.
Other protective bones:
Spine - protects spinal cord
Rib cage - protects heart and lungs
Pelvic girdle - protects reproductive organs
Answer: Option 4 → Skull
SSC GD 2026 – 4 May 2026 Shift 1 · Plant hormones and tropic movements

Q49. Which of the following is an example of chemotropism in plants?

  1. (a) Shoot bending towards light
  2. (b) Root growing downwards
  3. (c) Pollen tube growing towards ovule
  4. (d) Leaf folding on touch
Answer & solution

Answer: (c) Pollen tube growing towards ovule

Correct Answer: Pollen tube growing towards ovule — Option (c)
Chemotropism is the growth or movement of a plant organ in response to a chemical stimulus. The classic example is the pollen tube growing towards the ovule in response to chemical signals (such as sugars and other attractants) secreted by the ovule and style. This directional growth ensures successful fertilization.
Option (a) Shoot bending towards light — Incorrect: This is phototropism (response to light), not chemotropism.
Option (b) Root growing downwards — Incorrect: This is geotropism/gravitropism (response to gravity), not chemotropism.
Option (d) Leaf folding on touch — Incorrect: This is thigmonasty or seismonasty (response to touch/mechanical stimulus), not chemotropism.
SSC GD 2026 – 4 May 2026 Shift 3 · Endocrine glands and hormones

Q50. Which gland secretes Growth Hormone (GH)?

  1. (a) Thyroid gland
  2. (b) Adrenal gland
  3. (c) Pituitary gland
  4. (d) Pancreas
Answer & solution

Answer: (c) Pituitary gland

Correct Answer: Pituitary gland — Option (c)
The Pituitary gland (also called the 'master gland') secretes Growth Hormone (GH), also known as Somatotropin. GH is produced by the anterior pituitary and stimulates growth, cell reproduction, and regeneration. It promotes bone and muscle growth during childhood and adolescence. The pituitary gland also secretes many other important hormones like TSH, ACTH, FSH, and LH.
Option (a) Thyroid gland — Incorrect: The thyroid gland secretes thyroxine (T3 and T4) and calcitonin, not Growth Hormone.
Option (b) Adrenal gland — Incorrect: The adrenal glands secrete hormones like adrenaline (epinephrine), cortisol, and aldosterone, not Growth Hormone.
Option (d) Pancreas — Incorrect: The pancreas secretes insulin, glucagon, and digestive enzymes, not Growth Hormone.
SSC GD 2026 – 29 April 2026 Shift 1 · Peripheral and autonomic nervous system

Q51. Heartbeat is what type of action?

  1. (a) Reflex action
  2. (b) Involuntary action
  3. (c) Voluntary action
  4. (d) Coordinated action
Answer & solution

Answer: (b) Involuntary action

Correct Answer: Involuntary action — Option (b)
Heartbeat is an involuntary ( अनैच्छिक ) action — it occurs automatically without conscious control. Explanation: The heart is a cardiac muscle that contracts and relaxes rhythmically; The heartbeat is controlled by the autonomic nervous system (specifically the sympathetic and parasympathetic nervous systems) and the heart's own electrical conduction system (sinoatrial node, or the 'natural pacemaker'); A normal adult heart beats 60-100 times per minute at rest; The sinoatrial (SA) node in the right atrium generates the electrical impulse that initiates each heartbeat, spreading to the atrioventricular (AV) node and then to the ventricles; This entire process happens automatically, without any conscious effort or decision — it is involuntary; While factors like stress, exercise, and medicines can alter the heart rate, the basic action itself is involuntary.
Option (a) Reflex action — Incorrect: Reflex actions are rapid, automatic responses to stimuli mediated by the spinal cord (like pulling a hand away from a hot object); heartbeat is not a reflex action — it is an involuntary rhythmic action controlled by the autonomic nervous system and the heart's own pacemaker.
Option (c) Voluntary action — Incorrect: Voluntary actions are conscious, deliberate movements controlled by the cerebral cortex (like walking, writing, or speaking); heartbeat is involuntary — we cannot start or stop it at will. The candidate incorrectly selected this option.
Option (d) Coordinated action — Incorrect: While heartbeat does involve coordination between different parts of the heart's conduction system, 'coordinated action' is not the specific biological classification for heartbeat; the correct classification is 'involuntary action' as it occurs without conscious control.
SSC GD 2026 – 28 April 2026 Shift 1 · Endocrine glands and hormones

Q52. Which hormone is mainly responsible for the changes in males during puberty?

  1. (a) Estrogen
  2. (b) Thyroxine
  3. (c) Testosterone
  4. (d) Adrenaline
Answer & solution

Answer: (c) Testosterone

Correct Answer: Testosterone — Option (c)
Testosterone is the primary male sex hormone (androgen) mainly responsible for the physical and physiological changes in males during puberty. Testosterone is produced primarily in the testes (by Leydig cells) and in small amounts by the adrenal glands. Changes caused by testosterone during puberty include: Growth of facial hair (beard and moustache); Growth of body hair (chest, underarms, pubic area); Deepening of the voice (voice box enlargement); Development and growth of the penis and testes; Increase in muscle mass and strength; Increase in height and bone density; Development of the Adam's apple; Production of sperm (spermatogenesis). Testosterone also influences behavior, libido, and mood. It is a steroid hormone derived from cholesterol.
Option (a) Estrogen — Incorrect: Estrogen is the primary female sex hormone responsible for puberty changes in females (breast development, widening of hips, etc.); while males have small amounts of estrogen, it is not the primary hormone responsible for male puberty changes.
Option (b) Thyroxine — Incorrect: Thyroxine (T4) is produced by the thyroid gland and regulates metabolism, growth, and energy; it is not specifically responsible for the sexual development changes during male puberty.
Option (d) Adrenaline — Incorrect: Adrenaline (epinephrine) is a stress hormone produced by the adrenal glands that mediates the 'fight or flight' response; it is not responsible for the sexual development changes during male puberty.
RRB NTPC GL CBT-1 2025-26 – 24 March 2026 Shift 3 · Sense organs (eye, ear, nose, tongue, skin)

Q53. Which type of receptors in the human body are responsible for detecting taste?

  1. (a) Olfactory receptors
  2. (b) Thermo receptors
  3. (c) Auditory receptors
  4. (d) Gustatory receptors
Answer & solution

Answer: (d) Gustatory receptors

Topic: Sensory Receptors in Human Body
Gustatory receptorsare specialized sensory cells located on taste buds of the tongue.
They detect five basic tastes: sweet, sour, salty, bitter, and umami.
Other receptors: Olfactory (smell), Thermo (temperature), Auditory (sound).
Answer: Option 4 → Gustatory receptors
RRB Technician Grade III 2025-26 – 10 March 2026 Shift 2 · Neuron and nerve impulse

Q54. What is the primary function of the axon in a neuron?

  1. (a) Provide structural support to the neuron.
  2. (b) Store neurotransmitters for later use.
  3. (c) Transmit electrical impulses to other neurons or target organs.
  4. (d) Supply nutrients to the cell body.
Answer & solution

Answer: (c) Transmit electrical impulses to other neurons or target organs.

The axon is a long, slender projection of a neuron.
Its main role is to transmit electrical impulses away from the neuron's cell body.
These impulses are sent to other neurons, muscles, or glands.
This function is vital for communication within the nervous system.
RRB Technician Grade III 2025-26 – 6 March 2026 Shift 2 · Neuron and nerve impulse

Q55. Choose a term to complete analogy.
Axon : Single long process :: Dendrite : _______________

  1. (a) Protective connective tissue
  2. (b) Cell body with nucleus
  3. (c) Rapid stimulus transmission
  4. (d) Many short, branched parts
Answer & solution

Answer: (d) Many short, branched parts

Axon is a single long nerve fibre that transmits impulses away from the cell body.
Dendrites are many short, branched projections that receive signals and conduct them to the cell body.
Therefore, the correct analogy is: Dendrite : Many short, branched parts.
Final answer: Option 4
SSC MTS 2025 – 20 February 2026 Shift 2 · Neuron and nerve impulse

Q56. What does the chemical reaction at the dendritic tip of a nerve cell in animals create?

  1. (a) A muscle contraction
  2. (b) A reflex action
  3. (c) A hormonal response
  4. (d) An electrical impulse
Answer & solution

Answer: (d) An electrical impulse

Correct Answer: An electrical impulse (Option 4)
Dendrites are the branch-like extensions of a neuron that receive signals from other neurons. When a chemical reaction (neurotransmitter binding) occurs at the dendritic tip, it creates an electrical impulse (action potential) that travels along the neuron's axon to pass the signal onward.
Why other options are wrong:
Option 1 – Muscle contraction occurs at the neuromuscular junction (effector), not at the dendritic tip.
Option 2 – A reflex action is a complete response pathway involving multiple neurons; it is not created at the dendritic tip alone.
Option 3 – Hormonal responses are produced by endocrine glands, not by chemical reactions at nerve dendrites.
SSC MTS 2025 – 17 February 2026 Shift 3 · Brain - parts and functions

Q57. What main role does the fluid-filled balloon inside the skull play in protecting the brain?

  1. (a) It provides shock absorption
  2. (b) It helps in nutrient absorption
  3. (c) It aids in sensory perception
  4. (d) It regulates blood flow
Answer & solution

Answer: (a) It provides shock absorption

The fluid-filled structure inside the skull is the cerebrospinal fluid (CSF), which acts as a cushion and provides shock absorption to protect the brain from physical impact. It does not primarily help in nutrient absorption, sensory perception, or blood flow regulation — those are functions of other structures.
SSC MTS 2025 – 16 February 2026 Shift 1 · Hormonal disorders

Q58. Which of the following condition can result from a deficiency of growth hormone in childhood in humans?

  1. (a) Goitre
  2. (b) Dwarfism
  3. (c) Hyperthyroidism
  4. (d) Scurvy
Answer & solution

Answer: (b) Dwarfism

Deficiency of growth hormone (GH) — produced by the anterior pituitary gland — in childhood results in Dwarfism (also known as pituitary dwarfism). The child fails to grow at a normal rate, resulting in short stature and proportionate but underdeveloped body.
Why other options are incorrect:
- Goitre: Caused by iodine deficiency or thyroid gland dysfunction; not related to growth hormone.
- Hyperthyroidism: An overactive thyroid gland condition; not caused by growth hormone deficiency.
- Scurvy: Caused by deficiency of Vitamin C; not related to growth hormone.
SSC MTS 2025 – 12 February 2026 Shift 1 · Brain - parts and functions

Q59. Which is the main coordinating centre of the human body?

  1. (a) Spleen
  2. (b) Brain
  3. (c) Liver
  4. (d) Lung
Answer & solution

Answer: (b) Brain

Correct Answer: Option 2 – Brain
The brain is the main coordinating centre of the human body. It receives sensory information from various parts of the body, processes it, and sends appropriate response signals. It controls voluntary and involuntary actions, thinking, memory, and regulates all body functions through the nervous system.
Why other options are wrong:
Option 1 (Spleen): The spleen is part of the lymphatic system; it filters blood but does not coordinate body functions.
Option 3 (Liver): The liver performs metabolic functions such as detoxification and bile production; it is not a coordinating centre .
Option 4 (Lung): The lung is a respiratory organ involved in gas exchange; it has no coordinating role.
SSC MTS 2025 – 12 February 2026 Shift 3 · Hormonal disorders

Q60. Which of the following condition might require someone to reduce their sugar intake and take insulin injections?

  1. (a) Goitre
  2. (b) Dwarfism
  3. (c) Diabetes
  4. (d) Scurvy
Answer & solution

Answer: (c) Diabetes

Correct Answer: Option 3 – Diabetes
Diabetes mellitus is a metabolic disorder characterised by high blood glucose levels. In Type 1 diabetes, the pancreas produces little or no insulin, so insulin injections are required. In Type 2 diabetes, the body does not use insulin properly. Both types require reduced sugar intake. Insulin injections are prescribed when the body cannot regulate blood sugar naturally.
Why other options are wrong:
Option 1 (Goitre): Caused by iodine deficiency or thyroid disorders; not related to sugar or insulin.
Option 2 (Dwarfism): Caused by growth hormone deficiency; not related to insulin or sugar intake.
Option 4 (Scurvy): Caused by Vitamin C deficiency; treated with Vitamin C supplementation, not insulin.
SSC MTS 2025 – 10 February 2026 Shift 2 · Endocrine glands and hormones

Q61. Which of the following statement is correct regarding doping?
I. EPO is a peptide hormone.
II. EPO is released from the kidneys.

  1. (a) Only I
  2. (b) Only II
  3. (c) Both I and II
  4. (d) Neither I nor II
Answer & solution

Answer: (c) Both I and II

Correct Answer: 3 – Both I and II.
EPO stands for Erythropoietin. Both statements are correct:
Statement I is correct: EPO is a glycoprotein/peptide hormone that regulates red blood cell production. It is classified as a peptide hormone and is prohibited in sports as a performance-enhancing drug (it increases red blood cells and oxygen-carrying capacity).
Statement II is correct: EPO is primarily produced and released by the interstitial fibroblast cells in the kidneys (approximately 90% is produced in the kidneys; 10% in the liver).
Therefore, Both I and II are correct statements about EPO in the context of doping.
SSC MTS 2025 – 9 February 2026 Shift 1 · Endocrine glands and hormones

Q62. Which among the following gland in human body is located in lowermost part of body?

  1. (a) Pineal gland
  2. (b) Pituitary gland
  3. (c) Thyroid gland
  4. (d) Adrenal gland
Answer & solution

Answer: (d) Adrenal gland

Correct Answer: 4 (Adrenal gland)
Among the four options, the Adrenal glands are located at the lowermost position in the body:
- Pineal gland: located in the brain (epithalamus region)
- Pituitary gland: located at the base of the brain
- Thyroid gland: located in the neck region
- Adrenal gland: located on top of each kidney, in the abdominal/lumbar region (lower than all the above)
Option 1 (Pineal gland) is incorrect - it is located in the brain.
Option 2 (Pituitary gland) is incorrect - it is at the base of the brain.
Option 3 (Thyroid gland) is incorrect - the candidate chose this wrong option; the thyroid is in the neck.
SSC MTS 2025 – 9 February 2026 Shift 2 · Plant hormones and tropic movements

Q63. Which direction do roots of a plant typically grow in response to light?

  1. (a) Towards light
  2. (b) Away from light
  3. (c) Always parallel to the ground
  4. (d) Away from gravity
Answer & solution

Answer: (b) Away from light

Correct Answer: 2 – Away from light.
Roots exhibit negative phototropism – they grow away from light. This helps them penetrate into the soil where there is moisture and nutrients. In contrast, shoots grow towards light (positive phototropism).
Option 1 (Towards light) describes positive phototropism, which is the behaviour of shoots, not roots.
Option 3 (Always parallel to ground) is incorrect – roots grow downward into the soil.
Option 4 (Away from gravity) describes negative geotropism, which applies to shoots; roots grow towards gravity (positive geotropism).
SSC MTS 2025 – 6 February 2026 Shift 3 · Endocrine glands and hormones

Q64. Which of the following organ secretes adrenaline in animals?

  1. (a) Pituitary gland
  2. (b) Thyroid gland
  3. (c) Adrenal gland
  4. (d) Thymus gland
Answer & solution

Answer: (c) Adrenal gland

Correct Answer: 3 (Adrenal gland)
Adrenaline (also called epinephrine) is secreted by the Adrenal gland, specifically from the adrenal medulla (the inner part of the adrenal gland). Adrenaline is the 'fight or flight' hormone that prepares the body for emergency situations by increasing heart rate, blood pressure, and blood sugar levels.
Option 1 (Pituitary gland) is incorrect - the pituitary gland is the 'master gland' that secretes GH, TSH, ACTH, FSH, LH, ADH, oxytocin, etc., but not adrenaline.
Option 2 (Thyroid gland) is incorrect - the thyroid gland secretes thyroxine (T3 and T4) and calcitonin.
Option 4 (Thymus gland) is incorrect - the thymus secretes thymosin, which is involved in T-lymphocyte development.
SSC MTS 2025 – 4 February 2026 Shift 3 · Brain - parts and functions

Q65. In Humans, involuntary actions including blood pressure, salivation and vomiting are controlled by the ______ in the ______.

  1. (a) Medulla, hind-brain
  2. (b) Cerebrum, mid-brain
  3. (c) Spinal cord, fore-brain
  4. (d) Medulla, mid-brain
Answer & solution

Answer: (a) Medulla, hind-brain

Correct Answer: Medulla, hind-brain
The Medulla Oblongata, located in the hind-brain (brainstem), controls vital involuntary functions such as blood pressure, heartbeat, salivation, and vomiting. It acts as the control centre for the autonomic nervous system.
Why other options are wrong:
Cerebrum - Controls voluntary actions and is in the fore-brain, not mid-brain.
Spinal cord - Controls simple reflex actions; not in the fore-brain.
Medulla, mid-brain - Medulla is in the hind-brain, not the mid-brain.
Delhi Police Constable (Exe) 2025-26 – 6 January 2026 Shift 1 · Endocrine glands and hormones

Q66. The sleep-wake cycle in humans is controlled by a hormone secreted by the pineal gland. Which hormone regulates this circadian rhythm?

  1. (a) Cortisol
  2. (b) Melatonin
  3. (c) Adrenaline
  4. (d) Thyroxine
Answer & solution

Answer: (b) Melatonin

The correct answer is (b) Melatonin.
Melatonin is a hormone secreted by the pineal gland (a small endocrine gland in the brain) that regulates the circadian rhythm (24-hour biological clock) and sleep-wake cycle. Melatonin production increases in darkness (night), making us sleepy, and decreases in light (day). It is also sold as a supplement for jet lag and sleep disorders.
(a) Cortisol: A stress hormone secreted by the adrenal cortex; involved in the stress response, metabolism, and immune function; peaks in the morning to promote wakefulness but not the primary circadian regulator.
(c) Adrenaline (Epinephrine): Secreted by the adrenal medulla; the 'fight-or-flight' hormone; increases heart rate and alertness during stress; not a circadian rhythm regulator.
(d) Thyroxine: A thyroid hormone regulating metabolism and growth; not the primary regulator of the sleep-wake cycle.
Delhi Police Constable (Exe) 2025-26 – 5 January 2026 Shift 3 · Neuron and nerve impulse

Q67. Neurons transmit signals in the nervous system. Which part of a neuron primarily receives incoming electrical signals from other neurons?

  1. (a) Axon
  2. (b) Dendrite
  3. (c) Soma
  4. (d) Myelin sheath
Answer & solution

Answer: (b) Dendrite

The correct answer is (b) Dendrite.
Dendrites are the branched, tree-like extensions of a neuron that primarily receive incoming electrical/chemical signals from other neurons (via synapses). They carry signals toward the cell body (soma). The name 'dendrite' comes from the Greek word for 'tree' due to their branching appearance.
(a) Axon: The long tail-like extension that carries signals AWAY from the neuron's cell body to the next neuron or effector organ; not the primary receiver.
(c) Soma (cell body): Contains the nucleus and organelles; integrates signals from dendrites but is not the primary receiver.
(d) Myelin sheath: A fatty insulating layer that wraps around the axon to speed up signal transmission; not involved in receiving signals.
Delhi Police Constable (Exe) 2025-26 – 4 January 2026 Shift 2 · Endocrine glands and hormones

Q68. Which hormone is primarily responsible for regulating blood glucose levels by lowering them?

  1. (a) Insulin
  2. (b) Glucagon
  3. (c) Thyroxine
  4. (d) Adrenaline
Answer & solution

Answer: (a) Insulin

Insulin is secreted by the beta cells of the islets of Langerhans in the pancreas. It lowers blood glucose levels by facilitating the uptake of glucose by body cells and promoting its storage as glycogen in the liver.
(b) Incorrect: Glucagon is secreted by alpha cells of the pancreas and raises blood glucose by stimulating glycogen breakdown.
(c) Incorrect: Thyroxine is a thyroid hormone that regulates basal metabolic rate, not primarily blood glucose levels.
(d) Incorrect: Adrenaline (epinephrine) is a stress hormone that can temporarily increase blood glucose but does not primarily regulate it.
Delhi Police Constable (Exe) 2025-26 – 29 December 2025 Shift 3 · Endocrine glands and hormones

Q69. Which hormone is secreted by the pineal gland and regulates sleep-wake cycles in humans?

  1. (a) Cortisol
  2. (b) Melatonin
  3. (c) Insulin
  4. (d) Oxytocin
Answer & solution

Answer: (b) Melatonin

Melatonin is a hormone secreted by the pineal gland (a small endocrine gland in the brain) that regulates the circadian rhythm (sleep-wake cycle). Its secretion increases in darkness and decreases in bright light, signaling the body when it is time to sleep. Disruption of melatonin production (e.g., by artificial light) can cause sleep disorders.
(a) Incorrect: Cortisol is produced by the adrenal cortex; it is a stress hormone that regulates metabolism and immune response.
(c) Incorrect: Insulin is produced by beta cells of the pancreatic islets of Langerhans; it regulates blood glucose levels.
(d) Incorrect: Oxytocin is produced by the hypothalamus and stored in the posterior pituitary; it is associated with bonding, childbirth, and lactation.
Delhi Police Constable (Exe) 2025-26 – 24 December 2025 Shift 2 · Brain - parts and functions

Q70. Which of the following layers of the meninges is in direct contact with the brain tissue?

  1. (a) Dura mater
  2. (b) Arachnoid
  3. (c) Pia mater
  4. (d) Cerebrospinal fluid
Answer & solution

Answer: (c) Pia mater

The correct answer is Pia mater (Option 3).
The meninges are the three protective membranes covering the brain and spinal cord. From outermost to innermost: Dura mater (tough outer layer), Arachnoid mater (middle layer), and Pia mater (innermost). The Pia mater is the delicate, thin layer that directly adheres to and covers the surface of the brain and spinal cord tissue.
Option 1 - Dura mater: The Dura mater is the outermost, toughest meningeal layer; it is farthest from the brain tissue.
Option 2 - Arachnoid: The Arachnoid is the middle meningeal layer; it is separated from the Pia mater by the subarachnoid space filled with cerebrospinal fluid.
Option 4 - Cerebrospinal fluid: CSF is a fluid (not a membrane layer of the meninges); it fills the subarachnoid space between the arachnoid and pia mater.
Delhi Police Constable (Exe) 2025-26 – 22 December 2025 Shift 3 · Neuron and nerve impulse

Q71. What is the junction between two neurons called?

  1. (a) Synapse
  2. (b) Axon
  3. (c) Dendrite
  4. (d) Nucleus
Answer & solution

Answer: (a) Synapse

The correct answer is Synapse (Option 1).
A synapse is the junction between two neurons (or between a neuron and an effector cell) where nerve impulses are transmitted via neurotransmitters across the synaptic cleft.
Option 2 - Axon: The long, slender projection of a neuron that carries electrical impulses away from the cell body. It is not a junction.
Option 3 - Dendrite: The branched extensions of a neuron that receive signals from other neurons and conduct them toward the cell body.
Option 4 - Nucleus: The control center of the cell containing genetic material; it is not a junction between neurons.
SSC CPO Paper-1 2025 – 10 December 2025 Shift 2 · Neuron and nerve impulse

Q72. Read the below statements about synaptic transmission:
1. Synaptic cleft is the gap between two neurons.
2. Neurotransmitters are released from presynaptic terminals.
3. Axon hillock receives impulses from the next neuron.
Which of the above statements are correct?

  1. (a) Only 1 and 2 are correct
  2. (b) Only 1 and 3 are correct
  3. (c) Only 2 and 3 are correct
  4. (d) 1, 2 and 3 all are correct
Answer & solution

Answer: (a) Only 1 and 2 are correct

Correct Answer: Only 1 and 2 are correct
Statement 1: CORRECT. The synaptic cleft is the microscopic gap between the presynaptic neuron and the postsynaptic neuron across which neurotransmitters diffuse.
Statement 2: CORRECT. Neurotransmitters (like acetylcholine, dopamine) are stored in vesicles at the presynaptic terminal and released into the synaptic cleft upon nerve impulse arrival.
Statement 3: INCORRECT. The axon hillock is where the axon originates from the cell body. It INITIATES the nerve impulse (action potential) based on signals received by dendrites. It does not RECEIVE impulses from the next neuron — dendrites do that.
Therefore, only statements 1 and 2 are correct.
SSC Stenographer 2025 – 7 December 2025 Shift 2 · Plant hormones and tropic movements

Q73. Identify the correct pairing between a plant hormone and its primary physiological function:

  1. (a) Cytokinin – Initiating abscission of leaves
  2. (b) Ethylene – Ripening of fruits
  3. (c) Auxin – Promoting seed dormancy
  4. (d) Gibberellin – Stimulating cell division in roots
Answer & solution

Answer: (b) Ethylene – Ripening of fruits

Ethylene is the correct answer because it is the primary hormone responsible for fruit ripening. Cytokinin promotes cell division, not leaf abscission. Auxin prevents seed dormancy (it promotes germination), not increases it. Gibberellin mainly promotes stem elongation and seed germination, not only root cell division.
SSC CHSL Tier-1 2025 – 30 November 2025 Shift 1 · Plant hormones and tropic movements

Q74. Which of the following statement is correct regarding the plant hormones?
I. They help to coordinate growth, development and responses to the environment.
II. They are synthesised at places away from where they act and simply diffuse to the area of action.

  1. (a) Only I
  2. (b) Only II
  3. (c) Both I and II
  4. (d) Neither I nor II
Answer & solution

Answer: (c) Both I and II

Correct Answer: Option 3 – Both I and II
Both statements about plant hormones (phytohormones) are correct:
Statement I: Plant hormones coordinate growth, development, and responses to environmental stimuli (light, gravity, temperature, etc.) — this is their primary function. ✓
Statement II: Plant hormones are synthesised at specific sites (e.g., auxin at shoot tips) and transported/diffused to their target tissues where they exert their effects. ✓
Why other options are wrong:
Option 1 (Only I): Statement II is also correct; hormones are indeed synthesised away from their site of action.
Option 2 (Only II): Statement I is also correct; coordination of growth is a key function.
Option 4 (Neither I nor II): Both statements are factually accurate. The candidate incorrectly selected Only I.
SSC CHSL Tier-1 2025 – 30 November 2025 Shift 2 · Neuron and nerve impulse

Q75. In which direction does the electrical impulse travel in a nerve cell of an animal after being created?

  1. (a) From the dendrite to the cell body, then along the axon
  2. (b) From the axon to the dendrite
  3. (c) From the cell body to the axon
  4. (d) From the synapse to the muscle cells
Answer & solution

Answer: (a) From the dendrite to the cell body, then along the axon

Correct Answer: Option 1 – From the dendrite to the cell body, then along the axon
In a nerve cell (neuron), the electrical impulse (action potential) travels in a fixed direction: from the dendrites → cell body (soma) → along the axon → to the axon terminals (synapses). Dendrites receive incoming signals, the cell body processes them, and the axon transmits the impulse to the next neuron or effector organ.
Why other options are wrong:
Option 2 (Axon to dendrite): This is the reverse direction; nerve impulses never travel this way.
Option 3 (Cell body to axon): This is only partially correct — the impulse first arrives at the cell body from the dendrites. The candidate incorrectly selected this.
Option 4 (Synapse to muscle cells): The synapse is the end point of transmission, not the starting direction within the neuron.
SSC CHSL Tier-1 2025 – 29 November 2025 Shift 1 · Plant hormones and tropic movements

Q76. How do plants convey information about a touch from one cell to another?

  1. (a) Through specialized nerve tissue
  2. (b) By producing sound waves
  3. (c) By using electrical-chemical signals
  4. (d) Through changing colour of leaves
Answer & solution

Answer: (c) By using electrical-chemical signals

Plants convey information about touch (and other stimuli) from one cell to another through electrical-chemical signals. Unlike animals, plants lack nerve tissue, but use electrochemical gradients and chemical messengers for intercellular communication.
Plants have no nerve tissue or sound production for signalling ; colour change is not a rapid communication mechanism. Hence, By using electrical-chemical signals is correct.
SSC CHSL Tier-1 2025 – 29 November 2025 Shift 3 · Sense organs (eye, ear, nose, tongue, skin)

Q77. Which of the following sense is detected by gustatory receptors?

  1. (a) Sight
  2. (b) Smell
  3. (c) Taste
  4. (d) Hearing
Answer & solution

Answer: (c) Taste

Correct Answer: Option 3 – Taste
Gustatory receptors are taste receptors located on the taste buds of the tongue. They detect the sense of Taste, including the five basic tastes: sweet, sour, salty, bitter, and umami.
Why other options are wrong:
Option 1 (Sight): Sight is detected by photoreceptors (rods and cones) in the retina of the eye.
Option 2 (Smell): Smell is detected by olfactory receptors in the nasal cavity.
Option 4 (Hearing): Hearing is detected by mechanoreceptors (hair cells) in the cochlea of the inner ear.
SSC CHSL Tier-1 2025 – 28 November 2025 Shift 3 · Endocrine glands and hormones

Q78. What is the primary function of the growth hormone in humans?

  1. (a) Controls metabolism of carbohydrates and fats
  2. (b) Regulates blood sugar levels
  3. (c) Maintains body temperature
  4. (d) Regulates growth and development of the body
Answer & solution

Answer: (d) Regulates growth and development of the body

The primary function of Growth Hormone (GH), secreted by the anterior pituitary gland, is to regulate the growth and development of the body. It stimulates cell reproduction, cell regeneration, and growth in humans and animals.
Controls metabolism of carbohydrates and fats is a function of insulin and glucagon.
Regulates blood sugar levels is primarily the function of insulin (lowers) and glucagon (raises).
Maintains body temperature is a function of the hypothalamus and the thyroid hormone.
SSC CHSL Tier-1 2025 – 28 November 2025 Shift 1 · Brain - parts and functions

Q79. Involuntary actions like salivation and vomiting are regulated by which specific part of the hind-brain?

  1. (a) Cerebrum
  2. (b) Pons
  3. (c) Medulla
  4. (d) Hypothalamus
Answer & solution

Answer: (c) Medulla

The Medulla oblongata (part of the hind-brain / brain stem) regulates involuntary actions including salivation, vomiting, swallowing, breathing, heart rate, and blood pressure. It controls vital reflex actions essential for survival.
Cerebrum controls voluntary actions, thought, and memory; Pons controls breathing rate and is involved in sleep regulation; Hypothalamus regulates body temperature and hormone secretion. Hence, Medulla is correct.
SSC CHSL Tier-1 2025 – 27 November 2025 Shift 2 · Brain - parts and functions

Q80. Which of the following part of brain is responsible for the precision of voluntary actions and maintaining the posture and balance of the body?

  1. (a) Cerebrum
  2. (b) Cerebellum
  3. (c) Medulla
  4. (d) Hypothalamus
Answer & solution

Answer: (b) Cerebellum

The Cerebellum is responsible for the coordination and precision of voluntary movements, maintaining posture and balance of the body. It receives sensory input from the spinal cord and other brain regions and regulates motor control.
Cerebrum is the centre of thinking, memory, and conscious activities.
Medulla oblongata controls involuntary actions such as breathing and heart rate.
Hypothalamus regulates body temperature, hunger, thirst, and hormone secretion.
SSC CHSL Tier-1 2025 – 26 November 2025 Shift 2 · Plant hormones and tropic movements

Q81. What is the result of the uneven growth of the tendril in response to touch?

  1. (a) The tendril extends straight upward
  2. (b) The tendril circles around the object and clings to it
  3. (c) The tendril falls off the plant
  4. (d) The tendril withers away
Answer & solution

Answer: (b) The tendril circles around the object and clings to it

When a tendril comes in contact with an object (support), the cells on the side away from the object grow faster than the cells on the contact side. This uneven (differential) growth causes the tendril to curve and circle around the object and cling to it. This phenomenon is called Thigmotropism.
The tendril does not extend straight, fall off, or wither in response to touch. Hence, circling around and clinging is correct.
SSC CHSL Tier-1 2025 – 24 November 2025 Shift 1 · Endocrine glands and hormones

Q82. Which of the following endocrine gland releases hormone related to puberty in human females?

  1. (a) Ovaries
  2. (b) Pancreas
  3. (c) Pineal gland
  4. (d) Hypothalamus
Answer & solution

Answer: (a) Ovaries

Correct Answer: Ovaries (Option 1)
The Ovaries are the primary female reproductive endocrine glands that release estrogen and progesterone — hormones responsible for puberty in human females. Estrogen triggers the development of secondary sexual characteristics (breast development, widening of hips, pubic/armpit hair) at puberty. The ovaries start producing significant estrogen when triggered by FSH and LH from the pituitary gland at the onset of puberty.
Pancreas produces insulin and glucagon for blood sugar regulation — not puberty hormones.
Pineal gland produces melatonin (regulates sleep-wake cycle) — it does not directly release puberty hormones.
Hypothalamus releases GnRH (triggering the pituitary), but it is the ovaries that directly release the sex hormones (estrogen/progesterone) responsible for puberty.
SSC CHSL Tier-1 2025 – 22 November 2025 Shift 3 · Plant hormones and tropic movements

Q83. How does auxin affect the growth of the plant in response to light?

  1. (a) It causes all cells to grow equally
  2. (b) It stimulates cells on the light side to grow longer
  3. (c) It inhibits growth on the shady side
  4. (d) It stimulates cells on the shady side to grow longer
Answer & solution

Answer: (d) It stimulates cells on the shady side to grow longer

Correct Answer: It stimulates cells on the shady side to grow longer (Option 4)
Auxin is a plant hormone (phytohormone) that plays a key role in phototropism (the bending of plants toward light). When light falls on a plant from one side, auxin moves away from the light side to the shaded (dark) side of the stem. This higher concentration of auxin on the shady side stimulates those cells to elongate (grow longer) more than the cells on the light side. As a result, the plant bends toward the light source.
Why other options are wrong:
Option 1 - Causes all cells to grow equally: If all cells grew equally, there would be no bending toward light.
Option 2 - Stimulates cells on the light side to grow longer: Auxin actually concentrates on the SHADY side, not the light side.
Option 3 - Inhibits growth on the shady side: Auxin does the opposite — it stimulates (not inhibits) growth on the shady side.
SSC CHSL Tier-1 2025 – 15 November 2025 Shift 2 · Brain - parts and functions

Q84. Which of the following parts of the brain has separate areas specialised for hearing, smell, sight, etc.?

  1. (a) Fore brain
  2. (b) Mid brain
  3. (c) Hind brain
  4. (d) Spinal cord
Answer & solution

Answer: (a) Fore brain

The Fore brain (specifically the cerebrum/cerebral cortex) has distinct specialised areas for different senses: the visual cortex (sight), the auditory cortex (hearing), the olfactory area (smell), and other sensory and motor regions. The Mid brain is involved in visual and auditory reflexes. The Hind brain (medulla oblongata, pons, cerebellum) controls basic functions like heartbeat and balance. The Spinal cord relays signals but has no specialised sensory areas.
SSC CHSL Tier-1 2025 – 14 November 2025 Shift 1 · Endocrine glands and hormones

Q85. Which of the following hormones is associated with puberty in human males?

  1. (a) Adrenaline
  2. (b) Oestrogen
  3. (c) Thyroxin
  4. (d) Testosterone
Answer & solution

Answer: (d) Testosterone

Testosterone is the primary male sex hormone (androgen) produced by the testes. It is responsible for triggering puberty in males — including development of secondary sexual characteristics such as growth of facial and body hair, deepening of voice, and muscle development. Adrenaline is the fight-or-flight hormone; Oestrogen is the primary female sex hormone; Thyroxin regulates metabolism.
SSC CHSL Tier-1 2025 – 14 November 2025 Shift 3 · Peripheral and autonomic nervous system

Q86. Which of the following organ is part of central nervous system in humans?
I. Heart
II. Spinal cord

  1. (a) Only I
  2. (b) Only II
  3. (c) Both I and II
  4. (d) Neither I nor II
Answer & solution

Answer: (b) Only II

Correct Answer: Only II
The Central Nervous System (CNS) in humans consists of the Brain and the Spinal Cord only.
Statement I - Heart: The heart is part of the circulatory/cardiovascular system, NOT the CNS. It has its own electrical conduction system ( sino -atrial node) but is not part of the CNS.
Statement II - Spinal cord: The spinal cord IS part of the CNS. It serves as the main pathway for information connecting the brain and peripheral nervous system.
Why 'Only I' is wrong: Heart is not part of the CNS.
Why 'Both I and II' is wrong: Heart is not part of the CNS.
Why 'Neither' is wrong: Spinal cord is indeed part of the CNS.
SSC CGL Tier-1 2025 – 15 September 2025 Shift 3 · Brain - parts and functions

Q87. Which part of the human brain regulates the circadian rhythm?

  1. (a) Cerebellum
  2. (b) Hypothalamus
  3. (c) Medulla oblongata
  4. (d) Thalamus
Answer & solution

Answer: (b) Hypothalamus

• The Hypothalamus contains the Suprachiasmatic Nucleus (SCN) — the body's master biological clock.
• The SCN regulates circadian rhythms (roughly 24-hour physiological cycles) by responding to light signals from the retina.
• Cerebellum → coordinates movement and balance.
• Medulla oblongata → controls involuntary functions (heart rate, breathing).
• Thalamus → relay station for sensory signals.
• Answer: Hypothalamus
RRB NTPC UG CBT-1 2024-25 – 1 September 2025 Shift 1 · Neuron and nerve impulse

Q88. Which of the following is the correct terminology for the gap between two neurons where they communicate?

  1. (a) Dendritic cleft
  2. (b) Axonal gap
  3. (c) Node gap
  4. (d) Synaptic cleft
Answer & solution

Answer: (d) Synaptic cleft

SSC Selection Post 2025 (Phase XIII) – 29 August 2025 Shift 1 · Plant hormones and tropic movements

Q89. Read the following statements about plant hormones:
1. Auxins promote apical dominance.
2. Cytokinins promote senescence.
3. Ethylene accelerates fruit ripening.
Which of the above statements are correct?

  1. (a) Only 1 and 2 are correct
  2. (b) Only 1 and 3 are correct
  3. (c) Only 2 and 3 are correct
  4. (d) 1, 2 and 3 all are correct
Answer & solution

Answer: (b) Only 1 and 3 are correct

Correct Answer: Option 2 – Only 1 and 3 are correct
Statement 1 (TRUE): Auxins (particularly IAA — Indole-3-acetic acid) promote apical dominance — the phenomenon where the growing apical bud suppresses the growth of lateral (axillary) buds. High auxin concentrations from the shoot apex inhibit lateral bud growth, maintaining the plant's main axis dominance.
Statement 2 (FALSE): Cytokinins do NOT promote senescence — they DELAY senescence (aging/breakdown) in plant tissues. Cytokinins promote cell division, differentiation, and leaf greenness, and counteract the effects of ageing. It is Abscisic Acid (ABA) that promotes senescence and abscission, not cytokinins .
Statement 3 (TRUE): Ethylene is the primary plant hormone that accelerates fruit ripening. It stimulates the conversion of starch to sugars, softening of cell walls, and colour changes in fruits. Commercial fruit ripening (bananas, mangoes) uses ethylene gas or ethephon (ethylene-releasing compound).
Only Statements 1 and 3 are correct.
RRB NTPC UG CBT-1 2024-25 – 29 August 2025 Shift 3 · Hormonal disorders

Q90. Diabetes mellitus is caused by the inadequate secretion of which hormone?

  1. (a) Estrogen
  2. (b) Insulin
  3. (c) Adrenaline
  4. (d) Thyroxine
Answer & solution

Answer: (b) Insulin

SSC Selection Post 2025 (Phase XIII) – 29 July 2025 Shift 3 · Endocrine glands and hormones

Q91. Soybean products contain ________, which are similar to one of the human hormones.

  1. (a) phytoestrogen
  2. (b) manihotoxin
  3. (c) taxol
  4. (d) orphine
Answer & solution

Answer: (a) phytoestrogen

Correct Answer: Option 1 – phytoestrogen
Soybean products are rich in phytoestrogens — plant-derived compounds (primarily isoflavones: genistein, daidzein, glycitein ) that are structurally and functionally similar to human estrogen (the female sex hormone). Phytoestrogens can bind to estrogen receptors in the human body and exert weak estrogen-like effects. They are found in soy foods (tofu, soy milk, edamame, miso). Research links soy phytoestrogens to potential benefits including reduced menopausal symptoms, cardiovascular protection, and bone health.
Option 2 ( manihotoxin ): A cyanogenic glycoside found in cassava (Manihot esculenta) — a toxic compound, not a hormone-like substance in soybeans.
Option 3 ( taxol ): Paclitaxel (Taxol) is an anticancer drug originally derived from the Pacific yew tree (Taxus brevifolia ); not found in soybeans.
Option 4 ( orphine ): Not a recognised chemical compound in standard biochemistry; a distractor.
SSC Selection Post 2025 (Phase XIII) – 26 July 2025 Shift 3 · Plant hormones and tropic movements

Q92. The first peptide to be produced after wounding in the tomato plant is ________.

  1. (a) Systemin
  2. (b) Ricin
  3. (c) Jasmonic acid
  4. (d) Saicyclic acid
Answer & solution

Answer: (a) Systemin

Correct Answer: Option 1 – Systemin
Systemin is an 18-amino acid peptide hormone discovered in tomato (Solanum lycopersicum ) by Clarence Ryan and Gregory Pearce in 1991. It is the first plant peptide hormone identified as a systemic wound signal. When herbivores wound the plant, systemin is released and travels through the phloem to activate defense genes throughout the plant, triggering production of protease inhibitors that deter further herbivory.
Option 2 (Ricin): A highly toxic protein from castor bean (Ricinus communis); not a wound-response peptide in tomatoes.
Option 3 ( Jasmonic acid): A lipid-derived plant hormone involved in wound signaling — its synthesis is triggered downstream of systemin, but jasmonic acid itself is not a peptide.
Option 4 ( Saicyclic /Salicylic acid): A plant hormone involved in systemic acquired resistance; not the first peptide produced after wounding in tomatoes.
SSC Selection Post 2025 (Phase XIII) – 25 July 2025 Shift 3 · Plant hormones and tropic movements

Q93. The first peptide to be produced after wounding in the tomato plant is ________.

  1. (a) Systemin
  2. (b) Ricin
  3. (c) Jasmonic acid
  4. (d) Saicyclic acid
Answer & solution

Answer: (a) Systemin

Correct Answer: Option 1 – Systemin
Systemin is an 18-amino acid peptide hormone first discovered in tomato (Solanum lycopersicum ) by Clarence Ryan and Gregory Pearce in 1991. It is the first plant peptide hormone identified that functions as a systemic wound signal — released from damaged cells when a herbivore chews the plant, it travels through the phloem to activate defense gene expression throughout the plant, triggering production of protease inhibitors that deter further herbivory.
Option 2 (Ricin): A highly toxic protein found in castor bean (Ricinus communis); it is a lectin/toxin, not a wound-response peptide in tomatoes.
Option 3 ( Jasmonic acid): A plant hormone involved in wound response signaling, but it is a lipid-derived compound (not a peptide); its synthesis is triggered downstream of systemin signaling.
Option 4 ( Saicyclic acid/Salicylic acid): A plant hormone involved in systemic acquired resistance; not the first peptide produced after wounding.
RRB NTPC GL CBT-1 2024-25 – 17 June 2025 Shift 3 · Endocrine glands and hormones

Q94. Among the islet cells of the pancreas, which cell type secretes the hormone that primarily raises blood glucose levels?

  1. (a) Alpha cells
  2. (b) Beta cells
  3. (c) Delta cells
  4. (d) PP cells
Answer & solution

Answer: (a) Alpha cells

RRB NTPC GL CBT-1 2024-25 – 16 June 2025 Shift 2 · Peripheral and autonomic nervous system

Q95. Afferent neurons in the peripheral nervous system are responsible for which of the following?

  1. (a) Integrating reflex responses at the spinal cord level only
  2. (b) Conveying motor commands from the brain to muscles
  3. (c) Transmitting sensory information from receptors to the central nervous system
  4. (d) Facilitating secretion of neurotransmitters exclusively
Answer & solution

Answer: (c) Transmitting sensory information from receptors to the central nervous system

RRB NTPC GL CBT-1 2024-25 – 10 June 2025 Shift 1 · Neuron and nerve impulse

Q96. The synapse’s effectiveness in transmitting nerve impulses is most critically determined by which of the following?

  1. (a) The diameter of the axon
  2. (b) The length of the dendritic arborisation
  3. (c) The concentration of neurotransmitter and the number of receptors in the postsynaptic membrane
  4. (d) The presence of myelin sheaths along the dendrites
Answer & solution

Answer: (c) The concentration of neurotransmitter and the number of receptors in the postsynaptic membrane

RRB Technician Grade III 2024-25 – 30 December 2024 Shift 1 · Plant hormones and tropic movements

Q97. Why does the following action take place in plants?
Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking, and therefore in changing shape.

  1. (a) In immediate response to some stimulus
  2. (b) To maintain balance
  3. (c) To conserve energy
  4. (d) In fear
Answer & solution

Answer: (a) In immediate response to some stimulus

Correct Answer: Option 1 — In immediate response to some stimulus
Plants show two kinds of movement — growth-dependent (tropic) movements, which are slow, and growth-independent (nastic) movements, which are immediate responses to a stimulus. The action described here belongs to the second kind.
Since plants have no nervous system and no muscles, a plant cell changes its shape by changing the amount of water inside it. Water entering makes the cell swell (turgid) and water leaving makes it shrink (flaccid), and this change of shape produces the movement. This is exactly how the leaflets of the touch-me-not plant (Mimosa pudica) fold up the moment they are touched, and how guard cells open and close the stomata.
❌ Why the other options are incorrect
✗ To maintain balance — plants are fixed in the soil and do not need to balance their body as animals do while walking or running.
✗ To conserve energy — such water movement actually uses energy to pump ions into and out of the cells; saving energy is not its purpose.
✗ In fear — plants have no nervous system, so emotions like fear are impossible; the response is purely physical and chemical.
📌 SSC & Railway Exam Facts
• Mimosa pudica is the classic example of a growth-independent (nastic) movement.
• Tropic movements — phototropism (light), geotropism (gravity), hydrotropism (water), chemotropism (chemicals) and thigmotropism (touch).
• Auxin makes the shoot tip bend towards light; the growth of the pollen tube is chemotropism.
• Guard cells swell to open and shrink to close the stomata.
• Plant hormones — auxin, gibberellin and cytokinin (promoters) and abscisic acid (inhibitor, causes wilting).
RRB Technician Grade III 2024-25 – 30 December 2024 Shift 1 · Endocrine glands and hormones

Q98. which of the following is/ are correct related to Adrenalin hormone ?
(i) Heart beats faster
(ii) Breathing rate increases
(iii) Decreases blood pressure

  1. (a) (i), (ii) and (iii)
  2. (b) Only (ii) and (iii)
  3. (c) Only (i) and (ii)
  4. (d) Only (i) and (iii)
Answer & solution

Answer: (c) Only (i) and (ii)

Correct Answer: Option 3 — Only (i) and (ii)
Adrenaline (epinephrine) is secreted by the adrenal glands, which sit like caps on top of the kidneys. It is called the emergency hormone or the fight-or-flight hormone, because it is poured into the blood whenever a person is angry, frightened or excited.
Its effects are: the heart beats faster (i), so that more oxygen reaches the muscles; the breathing rate increases (ii) because of faster contraction of the diaphragm and rib muscles; blood is diverted from the skin and the digestive system to the skeletal muscles; and the blood pressure rises. Hence statement (iii) "Decreases blood pressure" is wrong — adrenaline increases blood pressure.
❌ Why the other options are incorrect
✗ (i), (ii) and (iii) — wrong; it accepts statement (iii), but adrenaline raises rather than lowers blood pressure.
✗ Only (ii) and (iii) — wrong; it rejects the true statement (i) and accepts the false statement (iii).
✗ Only (i) and (iii) — wrong; it leaves out the true statement (ii) and includes the false statement (iii).
📌 SSC & Railway Exam Facts
• The adrenal gland is also called the supra-renal gland; its cortex secretes cortisol and aldosterone.
• Adrenaline raises heart rate, breathing rate, blood sugar and blood pressure.
• Pituitary — the master gland; thyroid — thyroxine (needs iodine); pancreas — insulin.
• Noradrenaline is a closely related hormone secreted by the same gland.
• Iodine deficiency causes goitre; insulin deficiency causes diabetes mellitus.
RRB Technician Grade III 2024-25 – 30 December 2024 Shift 1 · Brain - parts and functions

Q99. Which of the following functions is NOT regulated by the medulla in the hind brain?

  1. (a) Blood pressure regulation
  2. (b) Regulation of hearing
  3. (c) Vomiting control
  4. (d) Salivary regulation
Answer & solution

Answer: (b) Regulation of hearing

Correct Answer: Option 2 — Regulation of hearing
Hearing is a sensation, and it is received and interpreted in the temporal lobe of the cerebrum, a part of the fore-brain. The medulla is concerned only with involuntary, life-supporting actions, not with the perception of sensations.
The medulla oblongata, a part of the hind-brain, controls the involuntary actions of the body — blood pressure, salivation, vomiting, heart beat, breathing, coughing and sneezing. Because it regulates the heart and the breathing, it is often called the vital centre, and an injury to it is usually fatal.
❌ Why the other options are incorrect
✗ Blood pressure regulation — an involuntary function clearly stated in NCERT as being controlled by the medulla.
✗ Vomiting control — the vomiting centre lies in the medulla, so this action is indeed regulated by it.
✗ Salivary regulation — salivation is another involuntary action listed under the control of the medulla.
📌 SSC & Railway Exam Facts
• Hind-brain = cerebellum + pons + medulla; the medulla controls involuntary actions.
• The cerebellum maintains posture and balance and makes movements precise (e.g. riding a bicycle).
• The cerebrum is the largest part of the brain — the seat of thinking, memory, will and sensations such as hearing, sight and smell.
• The hypothalamus controls hunger, thirst, sleep and body temperature.
• The brain is protected by the cranium (skull), three meninges and the cerebrospinal fluid (CSF).
RRB Technician Grade III 2024-25 – 30 December 2024 Shift 2 · Plant hormones and tropic movements

Q100. Select the INCORRECT statement related to tropism.

  1. (a) Phototropism – movement towards water
  2. (b) Geotropism – in response to the pull of earth or gravity
  3. (c) Chemotropism – movement towards chemical
  4. (d) Hydrotropism – movement towards water
Answer & solution

Answer: (a) Phototropism – movement towards water

Correct Answer: Option 1 — Phototropism – movement towards water
Tropism (tropic movement) is a directional growth movement of a plant part in response to an external stimulus. Growth towards the stimulus is positive tropism and growth away from it is negative tropism. Such movements are slow and are caused by unequal growth on the two sides of the organ, controlled mainly by the plant hormone auxin.
Phototropism is the movement of a plant part in response to light, not water. Auxin collects on the shaded side of a shoot, so those cells elongate more and the shoot bends towards the light (positive phototropism), while roots bend away from it (negative phototropism). Movement towards water is called hydrotropism, so Option 1 pairs the term with the wrong stimulus and is the incorrect statement.
❌ Why the other options are incorrect
✗ Geotropism – in response to the pull of earth or gravity — this pair is correct; roots show positive geotropism (grow downwards) and shoots show negative geotropism (grow upwards).
✗ Chemotropism – movement towards chemical — correct; the classic example is the growth of the pollen tube through the style towards the ovule.
✗ Hydrotropism – movement towards water — correct; roots bend towards a source of moisture in the soil.
📌 SSC & Railway Exam Facts
• Auxin is the hormone responsible for tropic (growth) movements; it promotes cell elongation.
• Thigmotropism is growth movement in response to touch — seen in the tendrils of pea and grapevine.
• Nastic movements, such as the drooping of Mimosa pudica leaves, are non-directional and are not growth movements.
• Other plant hormones — gibberellin (stem elongation), cytokinin (cell division), abscisic acid (growth inhibitor, wilting), ethylene (fruit ripening).
• Charles Darwin and Francis Darwin were the first to experiment on phototropism, using canary grass coleoptiles.
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