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Nutrition and Digestion PYQs – Biology, SSC & Railway

99 Nutrition and Digestion (Biology) questions asked in recent SSC and Railway exams, newest first, with exam, date & shift, answers and solutions.

📚 99 questionsSSC 32 · Railway 67
SSC Stenographer 2026 – 11 September 2026 Shift 2 · Vitamins - sources, functions and deficiency

Q1. Which vitamin deficiency is most likely to impair night vision?

  1. (a) Vitamin C
  2. (b) Vitamin A
  3. (c) Vitamin D
  4. (d) Vitamin K
Answer & solution

Answer: (b) Vitamin A

Answer: Option 2 — Vitamin A
The rod cells of the retina see in dim light using the pigment rhodopsin, which is made from retinal, a form of vitamin A.
Without enough vitamin A the rods cannot regenerate rhodopsin, so the eye fails in the dark — night blindness (nyctalopia).
Revision note — Vitamin A and the deficiency diseases
• Vitamin A = retinol; chemical name retinol, plant precursor beta-carotene; fat-soluble, stored in the liver.
• Sources: carrot, papaya, mango, spinach and green leafy vegetables (as carotene); liver, egg yolk, milk, butter, fish-liver oil (as retinol).
• Deficiency: night blindness first, then xerophthalmia (dry eye), Bitot's spots and keratomalacia, which can end in total blindness; also dry skin and poor immunity.
• Fat-soluble vitamins: A, D, E, K; water-soluble: B-complex and C.
• Vitamin C (ascorbic acid) → scurvy; Vitamin D (calciferol) → rickets in children, osteomalacia in adults; Vitamin K (phylloquinone) → delayed blood clotting.
• B1 (thiamine) → beriberi; B2 (riboflavin) → cheilosis; B3 (niacin) → pellagra; B12 (cobalamin) → pernicious anaemia; folic acid → anaemia and neural tube defects.
• Vitamins were named by Casimir Funk (1912); vitamin A was the first fat-soluble vitamin identified, by McCollum and Davis (1913).
Do not mix these up
• Night blindness vs colour blindness — night blindness is a dietary deficiency of vitamin A and is curable; colour blindness is genetic (X-linked) and affects the cone cells.
• Rickets vs osteomalacia — both are vitamin D deficiency; rickets bends the soft bones of children, osteomalacia weakens the bones of adults.
Also asked from this topic: the deficiency that causes night blindness (Vitamin A); the deficiency that causes beriberi (Vitamin B1); the fat-soluble vitamins (A, D, E, K).
SSC Stenographer 2026 – 9 September 2026 Shift 1 · Nutrients - carbohydrates, proteins, fats

Q2. Which part of the egg contains the highest protein content?

  1. (a) Shell
  2. (b) Yolk
  3. (c) Chalaza
  4. (d) Albumen
Answer & solution

Answer: (d) Albumen

Answer: Option 4 — Albumen
The albumen, the egg white, holds the largest total protein of any part of the egg.
About 3.6 g of the roughly 6.3 g in one large (50 g) egg sits in the white — close to 60 per cent of the whole.
Revision note — The egg as a food
• Albumen is about 88 per cent water and 10–11 per cent protein, with almost no fat.
• Its chief protein is ovalbumin, about 54 per cent of egg-white protein; the others are conalbumin, ovomucoid and lysozyme.
• The yolk stores the fat, cholesterol, lecithin, iron and the fat-soluble vitamins A, D, E and K. Yolk lecithin is the emulsifier that makes mayonnaise.
• The shell is about 95 per cent calcium carbonate. The chalazae are the two twisted protein cords that hold the yolk centred in the white.
• Egg protein is the reference protein of nutrition, with a biological value of 100, because its amino-acid pattern is closest to what the body needs.
• Proteins are the body-building nutrient and are digested down to amino acids; lysine is one of the essential amino acids the body cannot make for itself.
Do not mix these up
• Total content vs concentration — by concentration the yolk is richer, about 16 per cent protein, but it is far smaller, so by total quantity the white wins.
• Contains vs is richest in — a question asking which part contains the most protein wants the albumen; only a wording about percentage would point to the yolk.
• Albumen vs albumin — albumen is the egg white; albumin is a class of proteins, including the serum albumin of blood plasma.
Also asked from this topic: the nutrient that supports growth and healing (proteins); the end product of complete protein digestion (amino acids); an essential amino acid in the diet (lysine).
RRB Group D 2025-26 – 20 August 2026 Shift 1 · Nutrition in animals (amoeba, ruminants)

Q3. How does Paramecium ingest food?

  1. (a) By moving cilia toward a specific spot
  2. (b) By changing its entire body shape
  3. (c) By extending temporary pseudopodia
  4. (d) By direct absorption across the surface
Answer & solution

Answer: (a) By moving cilia toward a specific spot

Correct Answer:
Correct Answer: Option 1 – By moving cilia toward a specific spot
Explanation:
Parameciumis covered with hair-like structures calledcilia. The coordinated beating of cilia creates water currents that sweep food particles toward a specific region, theoral groove/cytostome (mouth region), where the food is then ingested.
Important Facts:
• Amoeba, not Paramecium, ingests food using temporary pseudopodia.
• Paramecium moves using cilia, which also assist in feeding.
RRB Group D 2025-26 – 19 August 2026 Shift 2 · Nutrition in animals (amoeba, ruminants)

Q4. Choose the incorrect statement regarding food intake in unicellular organisms.

  1. (a) Amoeba takes in food by forming pseudopodia.
  2. (b) Amoeba follows an autotrophic mode of nutrition.
  3. (c) Food is taken in through the process of endocytosis.
  4. (d) Paramecium uses cilia to move and to take in food.
Answer & solution

Answer: (b) Amoeba follows an autotrophic mode of nutrition.

Correct Answer:
Correct Answer: Option 2 – Amoeba follows an autotrophic mode of nutrition.
Explanation:
Amoeba is aheterotroph— specifically, it obtains food throughholozoic nutrition, engulfing food particles by forming temporary finger-like extensions called pseudopodia (a form of endocytosis called phagocytosis). It does not manufacture its own food, so calling it 'autotrophic' is incorrect. Paramecium, in contrast, uses cilia both for locomotion and to sweep food particles into its oral groove.
Important Facts:
• Autotrophs (like plants and some algae, e.g., Euglena in light) synthesize their own food; Amoeba cannot.
• Phagocytosis (engulfing solid food particles) is a specific type of endocytosis.
RRB Group D 2025-26 – 18 August 2026 Shift 1 · Human digestive system - organs

Q5. If peristaltic movements in the oesophagus were disrupted, what would most likely happen to the food after it is chewed and swallowed?

  1. (a) Saliva would increase
  2. (b) Starch would be broken down more quickly
  3. (c) Food would be digested faster
  4. (d) Food would not move efficiently to the stomach
Answer & solution

Answer: (d) Food would not move efficiently to the stomach

Peristalsis in the oesophagus
Peristalsis refers to the rhythmic, wave-like muscular contractions that push the food bolus down the oesophagus into the stomach.
If these movements were disrupted, the food would not be propelled efficiently towards the stomach, since the oesophagus does not rely on gravity alone (this is why swallowing works even upside down under normal conditions).
Correct Answer: Food would not move efficiently to the stomach
RRB Group D 2025-26 – 18 August 2026 Shift 3 · Digestive enzymes and juices

Q6. Carbohydrate digestion in humans begins in the mouth and is completed in which part of the digestive tract?

  1. (a) Small intestine
  2. (b) Large intestine
  3. (c) Stomach
  4. (d) Oesophagus
Answer & solution

Answer: (a) Small intestine

Concept: Digestion of Carbohydrates
Carbohydrate (starch) digestion begins in the mouth, where salivary amylase (ptyalin) breaks starch into maltose. This action is briefly halted in the acidic stomach (which lacks carbohydrate-digesting enzymes). Digestion resumes and is completed in thesmall intestine, where pancreatic amylase and intestinal enzymes (maltase, etc.) break down carbohydrates fully into simple sugars like glucose for absorption.
Correct Answer: Small intestine
RRB Group D 2025-26 – 14 August 2026 Shift 2 · Digestive enzymes and juices

Q7. What is the main function of saliva in the mouth during digestion?

  1. (a) It kills all bacteria
  2. (b) It absorbs nutrients
  3. (c) It transports food to the stomach
  4. (d) It breaks down starch into simple sugar
Answer & solution

Answer: (d) It breaks down starch into simple sugar

Answer: Option 4 – It breaks down starch into simple sugar.
• Salivary amylase (ptyalin)breaks starch into maltose (simple sugar)in the mouth.
RRB Group D 2025-26 – 13 August 2026 Shift 1 · Human digestive system - organs

Q8. Why is the small intestine able to fit into a compact space within the human body?

  1. (a) Thick walls
  2. (b) Rigid lining
  3. (c) Extensive coiling
  4. (d) Large diameter
Answer & solution

Answer: (c) Extensive coiling

Answer: Option 3 – Extensive coiling.
• The small intestine is very long but fits compactly because it ishighly coiled.
RRB Group D 2025-26 – 13 August 2026 Shift 1 · Digestive enzymes and juices

Q9. Which acid does our stomach produce and what is its pH?

  1. (a) Lactic acid; pH 3.5-4.5
  2. (b) Hydrochloric acid (HCl); pH 1.5-3.5
  3. (c) Acetic acid; pH 6.0-7.0
  4. (d) Citric acid; pH 6.5-7.0
Answer & solution

Answer: (b) Hydrochloric acid (HCl); pH 1.5-3.5

Answer: Option 2 – Hydrochloric acid (HCl); pH 1.5–3.5.
• The stomach secretesHCl, keeping a strongly acidic pH of about 1.5–3.5.
RRB Group D 2025-26 – 13 August 2026 Shift 1 · Digestive enzymes and juices

Q10. Why does the sight of or thought of delicious food make our mouths "water"?

  1. (a) Salivary glands secrete saliva
  2. (b) Digestive enzymes are released
  3. (c) Taste buds start moving quickly
  4. (d) Stomach acid increases rapidly
Answer & solution

Answer: (a) Salivary glands secrete saliva

Answer: Option 1 – Salivary glands secrete saliva.
• The sight/thought of food triggers thesalivary glandsto secrete saliva (a reflex).
RRB Group D 2025-26 – 13 August 2026 Shift 2 · Digestive enzymes and juices

Q11. What protects the stomach lining from damage by its own acid under normal conditions?

  1. (a) Pepsin release
  2. (b) Mucus secretion
  3. (c) Saliva entry
  4. (d) Acid increase
Answer & solution

Answer: (b) Mucus secretion

Answer: Option 2 – Mucus secretion.
•Mucussecreted by the stomach lining protects it from the corrosive HCl.
RRB Group D 2025-26 – 13 August 2026 Shift 2 · Nutrition in animals (amoeba, ruminants)

Q12. In which of the following organisms are pseudopodia used for capturing the food?

  1. (a) Paramecium
  2. (b) Hydra
  3. (c) Amoeba
  4. (d) Euglena
Answer & solution

Answer: (c) Amoeba

Answer: Option 3 – Amoeba.
•Amoebacaptures food using pseudopodia (phagocytosis).
RRB Group D 2025-26 – 13 August 2026 Shift 3 · Nutrition in animals (amoeba, ruminants)

Q13. How does Paramecium ensure that food particles are directed to its intake spot?

  1. (a) Utilises contractile vacuoles for food transport
  2. (b) Releases enzymes to move food particles
  3. (c) Forms pseudopodia to engulf food
  4. (d) Uses movement of cilia covering the cell surface
Answer & solution

Answer: (d) Uses movement of cilia covering the cell surface

Answer: Option 4 – Uses movement of cilia covering the cell surface.
•Parameciumsweeps food to its oral groove usingcilia.
RRB Group D 2025-26 – 12 August 2026 Shift 2 · Minerals - sources, functions and deficiency

Q14. _______ is necessary for the thyroid gland to make thyroxine hormone.

  1. (a) Calcium
  2. (b) Vitamin D
  3. (c) Iodine
  4. (d) Iron
Answer & solution

Answer: (c) Iodine

Answer: Option 3 – Iodine.
•Iodineis essential for the thyroid to make thyroxine; its deficiency causes goitre.
RRB Group D 2025-26 – 11 August 2026 Shift 3 · Nutrition in animals (amoeba, ruminants)

Q15. Which structure in Amoeba is primarily responsible for engulfing food particles?

  1. (a) Cytoplasm within the cell membrane
  2. (b) Temporary pseudopodia
  3. (c) Cilia covering cell surface
  4. (d) Cell wall surrounding the organism
Answer & solution

Answer: (b) Temporary pseudopodia

Answer: Option 2 – Temporary pseudopodia.
• Amoeba engulfs food using finger-likepseudopodia(phagocytosis).
RRB Group D 2025-26 – 11 August 2026 Shift 3 · Human digestive system - organs

Q16. Which organ helps crush food into smaller pieces during eating?

  1. (a) Salivary glands
  2. (b) Teeth
  3. (c) Stomach
  4. (d) Tongue
Answer & solution

Answer: (b) Teeth

Answer: Option 2 – Teeth.
•Teethcrush and grind food into smaller pieces (mechanical digestion).
RRB Group D 2025-26 – 6 August 2026 Shift 3 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q17. How do autotrophs fulfill their carbon and energy requirements?

  1. (a) By fermentation
  2. (b) By respiration
  3. (c) By photosynthesis
  4. (d) By digestion
Answer & solution

Answer: (c) By photosynthesis

Answer: Option 3 — By photosynthesis
Autotrophs obtain carbon and energy byphotosynthesis→ Option 3.
RRB Group D 2025-26 – 5 August 2026 Shift 1 · Nutrition in animals (amoeba, ruminants)

Q18. Which of the following statements about nutrition in single-celled organisms is INCORRECT?

  1. (a) Amoeba uses pseudopodia to engulf food
  2. (b) Paramecium takes in food with the help of cilia at a fixed spot
  3. (c) Paramecium engulfs food from all parts of its surface
  4. (d) Food is digested inside food vacuoles in Amoeba
Answer & solution

Answer: (c) Paramecium engulfs food from all parts of its surface

Answer: Option 3 — Paramecium engulfs food from all parts of its surface
This statement is INCORRECT:Parameciumtakes in food at afixed spot (oral groove)using cilia, not from all its surface. (Amoeba engulfs from any part.) → Option 3.
RRB Group D 2025-26 – 5 August 2026 Shift 1 · Nutrition in animals (amoeba, ruminants)

Q19. Which of the following CORRECTLY pairs the organism with the body part it uses for food intake?

  1. (a) Paramecium - cilia
  2. (b) Hydra - pseudopodia
  3. (c) Amoeba - flagella
  4. (d) Euglena - tentacles
Answer & solution

Answer: (a) Paramecium - cilia

Answer: Option 1 — Paramecium – cilia
Parameciumusesciliafor food intake. (Amoeba/Hydra use pseudopodia/tentacles; the other pairings are wrong.) → Option 1.
RRB Group D 2025-26 – 4 August 2026 Shift 2 · Digestive enzymes and juices

Q20. Why is maintaining a specific pH crucial for digestive enzymes in the human stomach?

  1. (a) To prevent the growth of harmful bacteria
  2. (b) To absorb water more efficiently
  3. (c) To neutralise excess stomach acid
  4. (d) To ensure the correct shape and activity of enzymes like pepsin
Answer & solution

Answer: (d) To ensure the correct shape and activity of enzymes like pepsin

Answer: Option 4 — To ensure the correct shape and activity of enzymes like pepsin
Enzymes work only at theiroptimum pH, which maintains their active 3-D shape. Pepsin needs the stomach's acidic pH to stay active → Option 4.
RRB Group D 2025-26 – 4 August 2026 Shift 2 · Digestive enzymes and juices

Q21. Which enzyme released by the gastric glands helps digest proteins in the stomach?

  1. (a) Lipase
  2. (b) Amylase
  3. (c) Pepsin
  4. (d) Maltase
Answer & solution

Answer: (c) Pepsin

Answer: Option 3 — Pepsin
Pepsindigests proteins in the stomach → Option 3.
RRB NTPC UG CBT-1 2025-26 – 15 June 2026 Shift 2 · Nutrients - carbohydrates, proteins, fats

Q22. The process of growth and healing in the body is supported by which food component?

  1. (a) Fats
  2. (b) Minerals
  3. (c) Vitamins
  4. (d) Proteins
Answer & solution

Answer: (d) Proteins

Topic: Nutrition - Body Building Foods
Proteinsare essential macronutrients made of amino acids.
Functions of Proteins:
• Growth and development of body tissues
• Repair and healing of damaged cells and tissues
• Building muscles, bones, skin, and organs
Sources: Meat, eggs, pulses, milk, fish, soybean.
Answer: Option 4 → Proteins
RRB NTPC UG CBT-1 2025-26 – 15 June 2026 Shift 2 · Human digestive system - organs

Q23. Which part of the small intestine in the human digestive system receives bile from the gall bladder and pancreatic juice from the pancreas through a common bile duct?

  1. (a) Ileum
  2. (b) Colon
  3. (c) Duodenum
  4. (d) Jejunum
Answer & solution

Answer: (c) Duodenum

Topic: Human Digestive System - Small Intestine
Small intestine has 3 parts:Duodenum, Jejunum, Ileum
Duodenumis the first and shortest part (25-30 cm)
Thecommon bile ductopens into duodenum athepatopancreatic ampulla
It receivesbilefrom gall bladder andpancreatic juicefrom pancreas
This is where major chemical digestion occurs
Answer: Option 3 → Duodenum
SSC GD 2026 – 31 May 2026 Shift 3 · Digestive enzymes and juices

Q24. From which two organs does the small intestine receive digestive secretions?

  1. (a) Stomach and Kidney
  2. (b) Liver and Pancreas
  3. (c) Pancreas and Spleen
  4. (d) Gallbladder and Lungs
Answer & solution

Answer: (b) Liver and Pancreas

Correct Answer: Liver and Pancreas (Option 2)
The small intestine (duodenum) receives digestive secretions from two main organs:
1. Liver: Produces bile (stored in the gallbladder), which is released into the duodenum via the bile duct. Bile emulsifies fats, aiding in their digestion and absorption.
2. Pancreas: Secretes pancreatic juice containing digestive enzymes (amylase, lipase, proteases) and bicarbonate. These enzymes break down carbohydrates, fats, and proteins in the duodenum.
Why others are wrong:
- Stomach and Kidney: Kidneys are excretory organs, not digestive organs.
- Pancreas and Spleen: The spleen is part of the immune/circulatory system, not the digestive system.
- Gallbladder and Lungs: Lungs are respiratory organs with no digestive function.
SSC GD 2026 – 21 May 2026 Shift 1 · Absorption and assimilation

Q25. What is the primary function of villi in the human small intestine?

  1. (a) Secreting digestive enzymes
  2. (b) Increasing surface area for absorption
  3. (c) Neutralizing stomach acid
  4. (d) Breaking down food particles
Answer & solution

Answer: (b) Increasing surface area for absorption

Correct Answer: Increasing surface area for absorption — Option (b)
The primary function of villi in the human small intestine is to increase the surface area available for absorption of digested nutrients. About intestinal villi: Villi (singular: villus) are tiny finger-like projections that line the inner wall of the small intestine; Height: Each villus is approximately 0.5 to 1.6 mm tall; Surface area enhancement: Villi increase the internal surface area of the small intestine dramatically — together with microvilli (on each villus cell, forming the 'brush border'), the total absorptive surface area of the small intestine is approximately 250-300 square metres (equivalent to a tennis court); Structure: Each villus contains: A network of blood capillaries (for absorbing glucose, amino acids, vitamins, and minerals into blood), A central lymph vessel called lacteal (for absorbing fatty acids and glycerol into the lymphatic system); Nutrients absorbed: Glucose and amino acids → absorbed into blood capillaries → portal vein → liver; Fatty acids and glycerol → absorbed into lacteals → lymphatic system → blood; Microvilli: Even smaller projections on the surface of each villus cell — further increasing surface area and containing brush border enzymes.
Option (a) Secreting digestive enzymes — Incorrect: While some enzyme secretion occurs in the small intestine (by intestinal glands and cells), this is NOT the PRIMARY function of villi; the primary function of villi is to increase surface area for absorption of nutrients.
Option (c) Neutralizing stomach acid — Incorrect: Neutralizing stomach acid is done by bicarbonate ions secreted by the pancreas (into the duodenum) and bile from the liver; villi do not neutralize stomach acid — their primary function is increasing surface area for absorption. The candidate selected this incorrect option.
Option (d) Breaking down food particles — Incorrect: Breaking down (digesting) food particles is done by digestive enzymes from the pancreas, liver (bile), and intestinal glands; villi's primary function is absorption (taking nutrients from the digested food into the body), not digestion.
RRB NTPC UG CBT-1 2025-26 – 8 May 2026 Shift 1 · Vitamins - sources, functions and deficiency

Q26. Which of the following is included among the water-soluble vitamins collectively grouped together in a specific vitamin class known as vitamin B complex?

  1. (a) Tocopherol
  2. (b) Retinol
  3. (c) Calciferol
  4. (d) Thiamin
Answer & solution

Answer: (d) Thiamin

Vitamin B Complex= Water-soluble vitamins
Checking each option:
Tocopherol→ Vitamin E (fat-soluble)
Retinol→ Vitamin A (fat-soluble)
Calciferol→ Vitamin D (fat-soluble)
Thiamin→ Vitamin B1 (water-soluble, part of B complex)
B Complex includes: B1, B2, B3, B5, B6, B7, B9, B12
Answer: Option 4 → Thiamin
RRB NTPC UG CBT-1 2025-26 – 8 May 2026 Shift 3 · Digestive enzymes and juices

Q27. The stomach secretes the enzyme pepsin to aid digestion. Pepsin mainly acts on which nutrient?

  1. (a) Carbohydrates
  2. (b) Fats
  3. (c) Proteins
  4. (d) Vitamins
Answer & solution

Answer: (c) Proteins

Topic:Digestive Enzymes - Pepsin
Pepsinis a proteolytic enzyme secreted by gastric glands in the stomach.
It breaks downproteinsinto smaller peptides in acidic medium (pH 1.5-2).
Secreted as inactive pepsinogen, activated by HCl.
Answer: Option 3 → Proteins
RRB NTPC UG CBT-1 2025-26 – 7 May 2026 Shift 1 · Vitamins - sources, functions and deficiency

Q28. Which of the following is a fat-soluble vitamin that helps in promotion of calcium absorption in the gut for bone health?

  1. (a) Vitamin A
  2. (b) Vitamin D
  3. (c) Vitamin B
  4. (d) Vitamin C
Answer & solution

Answer: (b) Vitamin D

Topic: Fat-Soluble Vitamins and Bone Health
Fat-soluble vitamins:A, D, E, K
Vitamin D functions:
• Promotes calcium absorption in intestine
• Essential for bone mineralization
• Maintains calcium-phosphorus balance
Vitamin A → Vision, immunity
Vitamin B → Water-soluble, not fat-soluble
Vitamin C → Water-soluble, collagen synthesis
Answer: Option 2 → Vitamin D
RRB NTPC UG CBT-1 2025-26 – 7 May 2026 Shift 2 · Digestive enzymes and juices

Q29. In human beings, the complete digestion of proteins results in the formation of which substances?

  1. (a) Fatty acids
  2. (b) Glucose
  3. (c) Glycerol
  4. (d) Amino acids
Answer & solution

Answer: (d) Amino acids

Protein Digestion in Humans
Proteins are complex molecules made of amino acids linked by peptide bonds.
Digestion process:
Stomach: Pepsin breaks proteins → polypeptides
Small intestine: Trypsin, chymotrypsin → smaller peptides
Final step: Peptidases →amino acids
Complete digestion of proteins yields only amino acids, which are absorbed by the small intestine.
Answer: Option 4 → Amino acids
SSC GD 2026 – 6 May 2026 Shift 1 · Minerals - sources, functions and deficiency

Q30. Which element is required by the thyroid gland to produce thyroxine?

  1. (a) Calcium
  2. (b) Iodine
  3. (c) Sodium
  4. (d) Potassium
Answer & solution

Answer: (b) Iodine

Correct Answer: Iodine — Option (b)
The thyroid gland requires iodine to produce its hormones — thyroxine (T4, containing 4 iodine atoms) and triiodothyronine (T3, containing 3 iodine atoms). Iodine is absorbed from the diet through the bloodstream and actively taken up by the thyroid gland. Deficiency of iodine leads to hypothyroidism and goitre (enlargement of the thyroid gland). This is why table salt is iodized — to prevent iodine deficiency disorders (IDD).
Option (a) Calcium — Incorrect: Calcium is required by the parathyroid gland (for regulating blood calcium levels) and for bone health, but it is not an ingredient of thyroxine. Iodine is the essential element for thyroid hormone synthesis.
Option (c) Sodium — Incorrect: Sodium is an electrolyte important for nerve function and fluid balance; it is not required for thyroxine production.
Option (d) Potassium — Incorrect: Potassium is essential for heart function and cellular metabolism; it has no role in the synthesis of thyroid hormones.
RRB NTPC GL CBT-1 2025-26 – 25 March 2026 Shift 2 · Nutrients - carbohydrates, proteins, fats

Q31. The energy stored in human liver and muscle tissues is mainly in the form of which carbohydrate?

  1. (a) Glycogen
  2. (b) Sucrose
  3. (c) Cellulose
  4. (d) Starch
Answer & solution

Answer: (a) Glycogen

Topic:Energy Storage in Human Body
Carbohydrate storage forms:
•Glycogen→ Animals (liver & muscles)
•Starch→ Plants (seeds, tubers)
•Cellulose→ Structural (cell walls)
•Sucrose→ Transport sugar (not storage)
Humans store excess glucose as glycogen.
Liver glycogen → maintains blood sugar.
Muscle glycogen → provides energy during activity.
Answer: Option 1 → Glycogen
RRB NTPC GL CBT-1 2025-26 – 17 March 2026 Shift 3 · Balanced diet and roughage

Q32. The Sattvic diet specifically includes which type of grain?

  1. (a) Highly refined flour
  2. (b) Sugary breakfast cereals
  3. (c) Polished white rice
  4. (d) Red rice and unpolished rice
Answer & solution

Answer: (d) Red rice and unpolished rice

Sattvic diet emphasizes pure, natural, unprocessed foods that promote clarity and health.
Key Principles:
• Whole grains in natural form
• Unrefined and unpolished foods
• Avoids heavy processing and refinement
Red rice and unpolished rice retain bran, nutrients, and natural properties—ideal for Sattvic diet.
Refined flour, sugary cereals, polished rice are processed—not Sattvic.
Answer: Option 4 → Red rice and unpolished rice
RRB NTPC GL CBT-1 2025-26 – 16 March 2026 Shift 2 · Nutrients - carbohydrates, proteins, fats

Q33. Which nutrient is primarily responsible for building and repairing tissues in the human body?

  1. (a) Carbohydrates
  2. (b) Fats
  3. (c) Proteins
  4. (d) Vitamins
Answer & solution

Answer: (c) Proteins

Proteins are the primary macronutrient responsible for building and repairing body tissues.
Functions of other nutrients:
• Carbohydrates → Main source of energy for the body.
• Fats → Long-term energy storage, insulation, absorption of fat-soluble vitamins.
• Vitamins → Regulatory functions, enzyme co-factors (do not build tissue directly).
• Proteins → Muscle building, tissue repair, enzymes, antibodies, hormones.
Key: Proteins are made of amino acids — the 'building blocks' of the body.
Answer: Option 3 → Proteins
RRB JE CBT-1 2025-26 – 20 February 2026 Shift 3 · Nutrition in animals (amoeba, ruminants)

Q34. Why is intracellular digestion suitable for unicellular organisms?

  1. (a) They lack specialized digestive organs.
  2. (b) They have large body cavities.
  3. (c) They lack digestive enzymes.
  4. (d) They depend on external digestion.
Answer & solution

Answer: (a) They lack specialized digestive organs.

Unicellular organisms do not have specialised digestive organs.
Therefore, digestion occurs inside the cell itself, known as intracellular digestion.
It allows them to break down food within their own cellular structures efficiently.
Hence, intracellular digestion is suitable because of the absence of specialised digestive systems.
Final answer: Option 1
SSC MTS 2025 – 19 February 2026 Shift 1 · Minerals - sources, functions and deficiency

Q35. Which mineral is essential for thyroid gland to produce thyroxin hormone in humans?

  1. (a) Calcium
  2. (b) Iodine
  3. (c) Manganese
  4. (d) Iron
Answer & solution

Answer: (b) Iodine

The correct answer is option 2.
Iodine is the essential mineral required by the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3) hormones. These hormones regulate metabolism, growth, and development. Deficiency of iodine leads to goitre (enlargement of thyroid gland) and hypothyroidism. Iodised salt is commonly used to prevent iodine deficiency.
Option 1 is incorrect: Calcium is essential for bone formation, muscle contraction, and nerve function — not for thyroxine production.
Option 3 is incorrect: Manganese is a trace mineral important for enzyme function and bone development, but not for thyroxine synthesis.
Option 4 is incorrect: Iron is essential for haemoglobin production and oxygen transport, not for thyroxine production.
SSC MTS 2025 – 19 February 2026 Shift 2 · Digestive enzymes and juices

Q36. On which food component does the salivary amylase act on in humans?

  1. (a) Proteins
  2. (b) Fats
  3. (c) Starch
  4. (d) Vitamins
Answer & solution

Answer: (c) Starch

The correct answer is option 3.
Salivary amylase (also called ptyalin) is an enzyme secreted by the salivary glands in the mouth. It acts on starch (a complex carbohydrate) and breaks it down into maltose (a simpler sugar). This is why chewing starchy food for a long time makes it taste slightly sweet — the starch is being converted to sugars.
Option 1 is incorrect: Proteins are broken down by protease enzymes (pepsin in the stomach, trypsin in the small intestine), not by salivary amylase.
Option 2 is incorrect: Fats are broken down by lipase enzymes, not by salivary amylase.
Option 4 is incorrect: Vitamins are absorbed directly and are not broken down by salivary amylase.
RRB JE CBT-1 2025-26 – 19 February 2026 Shift 1 · Digestive enzymes and juices

Q37. Which enzyme initiates carbohydrate digestion in the human mouth?

  1. (a) Trypsin released by pancreas
  2. (b) Pepsin secreted by gastric glands
  3. (c) Lipase secreted by liver
  4. (d) Salivary amylase present in saliva
Answer & solution

Answer: (d) Salivary amylase present in saliva

The digestion of carbohydrates begins in the human mouth.
Salivary amylase, present in saliva, starts breaking down starch into maltose.
Other enzymes listed act on proteins or fats or act later in the digestive process.
Trypsin is a pancreatic enzyme acting on proteins in the small intestine.
Pepsin is secreted by gastric glands and digests proteins in the stomach.
Lipase, secreted by the liver, breaks down fats.
Hence, carbohydrate digestion is initiated by salivary amylase in the mouth.
Final answer: Option 4
SSC MTS 2025 – 18 February 2026 Shift 3 · Human digestive system - organs

Q38. What role do teeth play in the digestion of food?

  1. (a) They secrete enzymes
  2. (b) They crush and grind the food into smaller particles
  3. (c) They produce saliva
  4. (d) They absorb nutrients from the food
Answer & solution

Answer: (b) They crush and grind the food into smaller particles

The correct answer is option 2.
Teeth play the role of mechanical digestion — they crush and grind food into smaller particles, increasing the surface area available for chemical digestion by enzymes. This process is called mastication (chewing) and takes place in the mouth.
Option 1 is incorrect: Enzymes are secreted by glands (salivary glands, pancreas, stomach lining, etc.), not by teeth.
Option 3 is incorrect: Saliva is produced by the salivary glands (parotid, submandibular, sublingual), not by teeth.
Option 4 is incorrect: Absorption of nutrients takes place in the small intestine, not by teeth.
SSC MTS 2025 – 17 February 2026 Shift 2 · Digestive enzymes and juices

Q39. Which of the following statement is correct regarding saliva?
I. Saliva secreted by the pituitary glands.
II. Saliva contains an enzyme called salivary amylase.

  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

Only Statement II is correct. Saliva is NOT secreted by the pituitary glands — it is secreted by the salivary glands (parotid, submandibular, and sublingual). Statement II is correct: saliva contains the enzyme salivary amylase (ptyalin), which begins the digestion of starch in the mouth.
SSC MTS 2025 – 16 February 2026 Shift 1 · Absorption and assimilation

Q40. Which part of the digestive system absorbs the most water from unabsorbed food in humans?

  1. (a) Stomach
  2. (b) Liver
  3. (c) Small intestine
  4. (d) Large intestine
Answer & solution

Answer: (d) Large intestine

The large intestine (colon) is responsible for absorbing the most water from the undigested food residue (chyme) that passes through from the small intestine. As food matter moves through the colon, water is absorbed back into the body, converting liquid waste into semi-solid faeces.
Why other options are incorrect:
- Stomach: The stomach primarily performs mechanical and chemical digestion; it absorbs very little water.
- Liver: The liver produces bile and performs metabolic functions; it is not part of the absorption pathway for water from food.
- Small intestine: While the small intestine does absorb some water (along with nutrients), the large intestine is specifically known for reabsorbing the bulk of the remaining water from unabsorbed food.
SSC MTS 2025 – 9 February 2026 Shift 3 · Human digestive system - organs

Q41. What is the name of the food pipe which takes food from the mouth to the stomach in humans?

  1. (a) Bladder
  2. (b) Oesophagus
  3. (c) Intestine
  4. (d) Spleen
Answer & solution

Answer: (b) Oesophagus

Correct Answer: 2 – Oesophagus .
The oesophagus (food pipe/gullet) is a muscular tube that connects the pharynx (throat) to the stomach. It carries food and liquids from the mouth to the stomach through a wave-like muscular movement called peristalsis.
Bladder (Option 1) stores urine – it is part of the urinary system.
Intestine (Option 3) is further in the digestive tract (small and large intestine), not the food pipe.
Spleen (Option 4) is a lymphatic organ that filters blood – not part of the digestive food pipe.
SSC MTS 2025 – 5 February 2026 Shift 1 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q42. Which of the following uses a parasitic nutritive strategy?
I. Cuscuta
II. Ticks

  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: Both I and II
Both use parasitic nutritive strategies:
Cuscuta ( Amarbel ) - A parasitic plant that attaches to the host plant using haustoria and absorbs water and nutrients. It has no chlorophyll and cannot photosynthesise .
Ticks - External parasites (ectoparasites) that feed on the blood of host animals, using a parasitic nutritive strategy.
Since both I and II are correct, the answer is Both I and II.
Delhi Police Constable (Exe) 2025-26 – 6 January 2026 Shift 3 · Absorption and assimilation

Q43. Which part of the human digestive system is primarily responsible for absorbing nutrients such as carbohydrates, proteins, fats, vitamins, and minerals?

  1. (a) Stomach
  2. (b) Large intestine
  3. (c) Small intestine
  4. (d) Liver
Answer & solution

Answer: (c) Small intestine

The correct answer is (c) Small intestine.
The small intestine is the primary site for digestion and absorption of nutrients in the human digestive system. It has three parts: duodenum (where most digestion occurs), jejunum, and ileum (where most absorption occurs). The inner surface has finger-like projections called villi and microvilli that increase the surface area for absorption of carbohydrates, proteins, fats, vitamins, and minerals.
(a) Stomach: Primarily responsible for mechanical digestion (churning) and chemical digestion of proteins (by pepsin); very limited absorption (only alcohol and some drugs).
(b) Large intestine: Primarily responsible for water absorption and formation of feces; not the primary site for nutrient absorption.
(d) Liver: Processes absorbed nutrients (received via portal vein), produces bile, and performs metabolic functions; it is not the site of direct nutrient absorption from food.
Delhi Police Constable (Exe) 2025-26 – 5 January 2026 Shift 3 · Digestive enzymes and juices

Q44. Which enzyme is responsible for breaking down dietary fats into fatty acids and glycerol for absorption in the human digestive system?

  1. (a) Carbohydrates
  2. (b) Proteins
  3. (c) Lipase
  4. (d) DNA
Answer & solution

Answer: (c) Lipase

The correct answer isLipase. [ ]
Why this option is correct:
🟢 Lipase: This is the primary digestive enzyme responsible for breaking down complex dietary lipids (fats and oils) into simpler, absorbable molecules like free fatty acids and glycerol. It is mainly produced by the pancreas (pancreatic lipase) and secreted into the small intestine. Minor amounts are also produced in the mouth (lingual lipase) and stomach (gastric lipase).
Delhi Police Constable (Exe) 2025-26 – 3 January 2026 Shift 2 · Digestive enzymes and juices

Q45. Which organ in the human body produces bile, a digestive fluid that helps emulsify fats for absorption in the small intestine?

  1. (a) Pancreas
  2. (b) Liver
  3. (c) Gall bladder
  4. (d) Duodenum
Answer & solution

Answer: (b) Liver

Bile is produced by the liver (hepatocytes/liver cells) and is then stored and concentrated in the gallbladder. When fatty food enters the small intestine, bile is released from the gallbladder into the duodenum to emulsify fats, making them easier for digestive enzymes to break down.
(a) Incorrect: The pancreas produces pancreatic juice (containing digestive enzymes and bicarbonate) and insulin/glucagon; it does not produce bile.
(b) Incorrect: The gall bladder stores and concentrates bile but does not produce it; bile is produced by the liver.
(c) Incorrect: The duodenum is the first part of the small intestine where bile and pancreatic juice are released; it does not produce bile.
Delhi Police Constable (Exe) 2025-26 – 3 January 2026 Shift 2 · Vitamins - sources, functions and deficiency

Q46. Certain vitamins play a crucial role in blood coagulation. Which vitamin is essential for the activation of clotting factors in the liver?

  1. (a) Vitamin A
  2. (b) Vitamin D
  3. (c) Vitamin K
  4. (d) Vitamin C
Answer & solution

Answer: (c) Vitamin K

Vitamin K is essential for blood coagulation (clotting). It activates several clotting factors (II, VII, IX, X) produced in the liver through a process called carboxylation. Deficiency of Vitamin K leads to impaired blood clotting and excessive bleeding. It is found in green leafy vegetables.
(a) Incorrect: Vitamin A is essential for vision, immune function, and cell growth; it is not involved in blood clotting.
(b) Incorrect: Vitamin D is essential for calcium absorption, bone health, and immune function; it is not directly involved in blood coagulation.
(c) Incorrect: Vitamin C is essential for collagen synthesis and antioxidant protection; while it helps with wound healing, it is not responsible for activating clotting factors.
Delhi Police Constable (Exe) 2025-26 – 29 December 2025 Shift 3 · Digestive enzymes and juices

Q47. Which organ serves as the storage site for bile, releasing it into the small intestine when fats are ingested for proper digestion?

  1. (a) Liver
  2. (b) Gall bladder
  3. (c) Pancreas
  4. (d) Stomach
Answer & solution

Answer: (b) Gall bladder

The gall bladder is a small pear-shaped organ located beneath the liver that stores bile (produced by the liver). When fatty foods are consumed, cholecystokinin (CCK) stimulates the gall bladder to contract and release bile into the small intestine (via the common bile duct) to emulsify and aid in the digestion of dietary fats.
(a) Incorrect: The liver produces bile but does not store it; the gall bladder is the storage organ.
(c) Incorrect: The pancreas produces digestive enzymes (lipase, amylase, protease) and insulin; it does not store bile.
(d) Incorrect: The stomach produces hydrochloric acid and gastric enzymes for protein digestion; it does not store bile.
Delhi Police Constable (Exe) 2025-26 – 23 December 2025 Shift 1 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q48. Which organisms break down food material outside their bodies and then absorb it?

  1. (a) Animals like cows and lions
  2. (b) Plants like grass and trees
  3. (c) Fungi like bread moulds , yeast, and mushrooms
  4. (d) Parasites like cuscuta and tape-worms
Answer & solution

Answer: (c) Fungi like bread moulds , yeast, and mushrooms

The correct answer is Fungi like bread moulds , yeast, and mushrooms (Option 3).
Fungi are saprotrophic organisms that secrete digestive enzymes outside their bodies to break down complex organic matter into simpler substances, which they then absorb through their cell walls. This process is called extracellular digestion.
Option 1 - Animals like cows and lions: Animals digest food internally through their digestive systems, not outside their bodies.
Option 2 - Plants like grass and trees: Plants are autotrophs that make their own food through photosynthesis; they do not break down external food material.
Option 4 - Parasites like cuscuta and tape-worms: Parasites absorb nutrients from host organisms but do not typically break down food outside their bodies with enzymes.
SSC CPO Paper-1 2025 – 12 December 2025 Shift 1 · Nutrients - carbohydrates, proteins, fats

Q49. Which amino acid is considered essential in human diet?

  1. (a) Alanine
  2. (b) Glycine
  3. (c) Lysine
  4. (d) Serine
Answer & solution

Answer: (c) Lysine

Correct Answer: Lysine (Option 3)
Essential amino acids are those that the human body cannot synthesize on its own and must be obtained from food. There are 9 essential amino acids: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine.
Lysine is one of the 9 essential amino acids. It is important for protein synthesis, calcium absorption, and production of hormones and enzymes.
Alanine is a non-essential amino acid — the body can synthesize it.
Glycine is a non-essential amino acid — the body can synthesize it.
Serine is a conditionally essential amino acid — generally classified as non-essential.
SSC CPO Paper-1 2025 – 11 December 2025 Shift 2 · Vitamins - sources, functions and deficiency

Q50. Which vitamin is synthesized by intestinal microbiota?

  1. (a) Vitamin C
  2. (b) Vitamin K
  3. (c) Vitamin E
  4. (d) Vitamin D
Answer & solution

Answer: (b) Vitamin K

Correct Answer: Vitamin K (Option 2)
Vitamin K (specifically Vitamin K2/Menaquinone) is synthesized by intestinal microbiota (gut bacteria) in the human colon. These bacteria produce Vitamin K2 which is absorbed by the large intestine. Vitamin K is essential for blood clotting and bone metabolism.
Vitamin C (Ascorbic acid) cannot be synthesized by the human body at all — it must be obtained entirely from diet.
Vitamin E is a fat-soluble antioxidant obtained from diet — not synthesized by gut bacteria.
Vitamin D is synthesized in the skin upon exposure to sunlight (UV radiation) — not by intestinal microbiota.
SSC CPO Paper-1 2025 – 9 December 2025 Shift 1 · Digestive enzymes and juices

Q51. Read the following statements about the human digestive system:
1. Bile emulsifies fats but does not contain enzymes.
2. Trypsinogen is activated by trypsin in the stomach.
3. Villi in the small intestine increase surface area for absorption.
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

Statement 1 is CORRECT: Bile (produced by the liver, stored in the gallbladder) emulsifies fats — it breaks large fat globules into smaller droplets to increase surface area for enzyme action. Bile contains no digestive enzymes.
Statement 2 is INCORRECT: Trypsinogen (the inactive precursor) is activated by enterokinase ( enteropeptidase ), an enzyme secreted by the intestinal mucosa — NOT in the stomach and NOT initially by trypsin.
Statement 3 is CORRECT: Villi (and microvilli forming the brush border) in the small intestine dramatically increase the surface area for nutrient absorption.
Therefore, only Statements 1 and 3 are correct.
SSC CHSL Tier-1 2025 – 27 November 2025 Shift 1 · Digestive enzymes and juices

Q52. The biological catalysts which help in the breakdown of food in humans known as _____.

  1. (a) Lymph
  2. (b) Mucus
  3. (c) Enzymes
  4. (d) Bile
Answer & solution

Answer: (c) Enzymes

Enzymes are biological catalysts — protein molecules that speed up chemical reactions in the body. In the digestive system, enzymes such as amylase (breaks down starch), pepsin (breaks down proteins), and lipase (breaks down fats) help in the breakdown of food.
Lymph is the fluid in the lymphatic system; Mucus is a protective secretion; Bile is a digestive juice produced by the liver that emulsifies fats but is not a catalyst/enzyme. Hence, Enzymes is correct.
SSC CHSL Tier-1 2025 – 24 November 2025 Shift 3 · Digestive enzymes and juices

Q53. What is the primary function of hydrochloric acid in the stomach of humans?

  1. (a) To neutralize the food
  2. (b) To create an alkaline medium
  3. (c) To create an acidic medium for enzyme action
  4. (d) To avoid digestion of proteins
Answer & solution

Answer: (c) To create an acidic medium for enzyme action

Correct Answer: To create an acidic medium for enzyme action (Option 3)
Hydrochloric acid (HCl) secreted by the parietal cells in the stomach serves primarily to create an acidic environment (pH 1.5–3.5). This acidic medium: (1) Activates the enzyme pepsinogen into active pepsin for protein digestion; (2) Kills harmful bacteria in ingested food; (3) Denatures proteins, making them more accessible for enzyme action; (4) Aids in the absorption of minerals like calcium and iron.
To neutralize the food — HCl is an acid, not a neutralizing agent; it makes the stomach environment acidic, not neutral.
To create an alkaline medium — HCl creates an ACIDIC medium, not alkaline. The duodenum uses bicarbonate to neutralize stomach acid.
To avoid digestion of proteins — this is the opposite of what HCl does; it PROMOTES protein digestion by activating pepsin.
SSC CHSL Tier-1 2025 – 17 November 2025 Shift 1 · Human digestive system - organs

Q54. Among the following organs, which is located on uppermost part of a human body?

  1. (a) Buccal Cavity
  2. (b) Anus
  3. (c) Bile Duct
  4. (d) Appendix
Answer & solution

Answer: (a) Buccal Cavity

The Buccal Cavity (oral cavity/mouth) is located in the head region, which is the topmost part of the human body. It is the beginning of the digestive system and is situated in the uppermost portion of the body. Why other options are wrong: Option 2 - Anus: Located at the bottom/posterior end of the body; it is the terminal opening of the digestive system. Option 3 - Bile Duct: Located in the abdominal region (connects liver, gallbladder, and small intestine), which is in the middle of the body. Option 4 - Appendix: A small pouch located in the lower right region of the abdomen, not in the uppermost part of the body.
SSC CHSL Tier-1 2025 – 15 November 2025 Shift 3 · Human digestive system - organs

Q55. Which of the following organs is the longest part of the alimentary canal in humans?

  1. (a) Liver
  2. (b) Small intestine
  3. (c) Buccal cavity
  4. (d) Oesophagus
Answer & solution

Answer: (b) Small intestine

The small intestine is the longest part of the alimentary canal in humans, measuring approximately 6 to 7 metres . It is divided into three parts: duodenum, jejunum, and ileum. It is the primary site for digestion and absorption of nutrients. Option 1 (Liver) is a digestive gland, not a part of the alimentary canal itself. Option 3 (Buccal cavity) is the mouth and is only a few centimetres . Option 4 ( Oesophagus ) is about 25 cm long.
SSC CHSL Tier-1 2025 – 12 November 2025 Shift 2 · Nutrition in animals (amoeba, ruminants)

Q56. What are the temporary finger-like extensions of the cell surface used by Amoeba to take in food called?

  1. (a) Flagella
  2. (b) Cilia
  3. (c) Vacuoles
  4. (d) Pseudopodia
Answer & solution

Answer: (d) Pseudopodia

Pseudopodia (meaning 'false feet') are temporary, finger-like cytoplasmic projections extended by Amoeba. They are used for locomotion and engulfing food particles through a process called phagocytosis. Flagella are long whip-like structures used for movement (e.g., in Euglena). Cilia are short hair-like projections (e.g., in Paramecium). Vacuoles are membrane-bound sacs used for storage or digestion — not extensions.
SSC CHSL Tier-1 2025 – 12 November 2025 Shift 2 · Nutrition in animals (amoeba, ruminants)

Q57. What are the temporary finger-like extensions of the cell surface used by Amoeba to take in food called?

  1. (a) Flagella
  2. (b) Cilia
  3. (c) Vacuoles
  4. (d) Pseudopodia
Answer & solution

Answer: (d) Pseudopodia

Correct Answer: Pseudopodia
Pseudopodia (singular: pseudopodium) are temporary, finger-like projections of the cell membrane and cytoplasm in Amoeba. They are used for:
- Locomotion (amoeboid movement)
- Capturing and engulfing food (phagocytosis)
Why other options are wrong:
- Flagella: Long, whip-like structures used for swimming movement (e.g., in Euglena, sperm cells).
- Cilia: Short, hair-like structures used for movement and creating water currents (e.g., in Paramecium).
- Vacuoles: Membrane-bound organelles used for storage, digestion, and waste removal; not extensions.
SSC CHSL Tier-1 2025 – 12 November 2025 Shift 3 · Digestive enzymes and juices

Q58. Which organ of digestive system secretes the enzyme lipase for digesting emulsified fats in humans?

  1. (a) Gall bladder
  2. (b) Liver
  3. (c) Pancreas
  4. (d) Small intestine
Answer & solution

Answer: (c) Pancreas

Correct Answer: Pancreas
The Pancreas secretes pancreatic lipase (also known as steapsin), which digests emulsified fats (triglycerides) in the small intestine, breaking them down into fatty acids and glycerol. The pancreas is both an exocrine gland (secreting digestive enzymes) and an endocrine gland (secreting insulin and glucagon).
Why other options are wrong:
- Gall bladder: Stores and releases bile (produced by liver), which emulsifies fats but does not produce lipase.
- Liver: Produces bile for emulsification of fats; does not secrete lipase.
- Small intestine: Produces intestinal lipase, but the primary enzyme for fat digestion comes from the pancreas.
SSC CGL Tier-1 2025 – 14 September 2025 Shift 3 · Nutrients - carbohydrates, proteins, fats

Q59. Which biomolecule acts as the primary energy storage in animals?

  1. (a) Glycogen
  2. (b) Starch
  3. (c) Cellulose
  4. (d) Sucrose
Answer & solution

Answer: (a) Glycogen

Glycogen is the primary energy storage carbohydrate in animals, stored mainly in the liver and muscles.
Starch is the primary energy storage in plants.
Cellulose is a structural carbohydrate in plant cell walls — not for energy storage.
Sucrose is a transport sugar in plants.
Answer: Glycogen
RRB NTPC UG CBT-1 2024-25 – 4 September 2025 Shift 1 · Nutrients - carbohydrates, proteins, fats

Q60. What is the main function of carbohydrates in the body?

  1. (a) It is crucial for growth.
  2. (b) It regulates hormones.
  3. (c) It provides energy.
  4. (d) It insulates the body.
Answer & solution

Answer: (c) It provides energy.

RRB NTPC UG CBT-1 2024-25 – 4 September 2025 Shift 1 · Minerals - sources, functions and deficiency

Q61. Which mineral helps in the formation of insulin granules, digestion, metabolism and functioning of the male prostate?

  1. (a) Phosphorus
  2. (b) Iron
  3. (c) Zinc
  4. (d) Nickel
Answer & solution

Answer: (c) Zinc

RRB NTPC UG CBT-1 2024-25 – 2 September 2025 Shift 1 · Minerals - sources, functions and deficiency

Q62. Which of the following minerals is essential for oxygen transport in the blood?

  1. (a) Calcium
  2. (b) Zinc
  3. (c) Magnesium
  4. (d) Iron
Answer & solution

Answer: (d) Iron

RRB NTPC UG CBT-1 2024-25 – 28 August 2025 Shift 1 · Nutrients - carbohydrates, proteins, fats

Q63. Proteins are mainly responsible for which of the following?

  1. (a) Providing quick energy
  2. (b) Growth and repair of tissues
  3. (c) Improving digestion
  4. (d) Enhancing memory power
Answer & solution

Answer: (b) Growth and repair of tissues

RRB NTPC UG CBT-1 2024-25 – 21 August 2025 Shift 2 · Vitamins - sources, functions and deficiency

Q64. Consider the following vitamins.1. Vitamin D2. Vitamin B123. Vitamin K4. Vitamin CWhich of them are water soluble?

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

Answer: (c) Only 2 and 4

RRB NTPC UG CBT-1 2024-25 – 21 August 2025 Shift 2 · Nutrients - carbohydrates, proteins, fats

Q65. Which of the following foods is a source of animal protein?

  1. (a) Pulses
  2. (b) Beans
  3. (c) Eggs
  4. (d) Nuts
Answer & solution

Answer: (c) Eggs

RRB NTPC UG CBT-1 2024-25 – 20 August 2025 Shift 2 · Balanced diet and roughage

Q66. Which of the following foods is a rich source of dietary fibre for human beings?

  1. (a) Chicken
  2. (b) Fish
  3. (c) Oats
  4. (d) Cheese
Answer & solution

Answer: (c) Oats

RRB NTPC UG CBT-1 2024-25 – 19 August 2025 Shift 2 · Nutrients - carbohydrates, proteins, fats

Q67. What happens to excess carbohydrates in the body?

  1. (a) They are turned into proteins.
  2. (b) They are converted into amino acids and stored.
  3. (c) They are converted into fat and stored.
  4. (d) They are excreted immediately.
Answer & solution

Answer: (c) They are converted into fat and stored.

RRB NTPC UG CBT-1 2024-25 – 18 August 2025 Shift 1 · Vitamins - sources, functions and deficiency

Q68. Consider the following vitamins.1. Vitamin A2. Vitamin B63. Vitamin C4. Vitamin DWhich of them is/are fat-soluble?

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

Answer: (d) Only 1 and 4

RRB NTPC UG CBT-1 2024-25 – 14 August 2025 Shift 2 · Balanced diet and roughage

Q69. Which of the following correctly represents the function of dietary fibre in the human diet?

  1. (a) Aids digestion
  2. (b) Increases cholesterol
  3. (c) Helps build muscle
  4. (d) Provides energy
Answer & solution

Answer: (a) Aids digestion

RRB NTPC UG CBT-1 2024-25 – 8 August 2025 Shift 1 · Nutrients - carbohydrates, proteins, fats

Q70. Which of the following is classified as micronutrients?

  1. (a) Fats
  2. (b) Carbohydrates
  3. (c) Vitamins
  4. (d) Proteins
Answer & solution

Answer: (c) Vitamins

SSC Selection Post 2025 (Phase XIII) – 31 July 2025 Shift 2 · Vitamins - sources, functions and deficiency

Q71. Which of the following combinations correctly matches the vitamin with its function and deficiency disorder?

  1. (a) Vitamin A → Promotes calcium absorption → Deficiency causes Scurvy
  2. (b) Vitamin D → Regulates vision pigments → Deficiency leads to Pellagra
  3. (c) Vitamin B₁₂ → Aids nerve function and red blood cell formation → Deficiency causes Pernicious anaemia
  4. (d) Vitamin C → Supports blood clotting → Deficiency leads to Night blindness
Answer & solution

Answer: (c) Vitamin B₁₂ → Aids nerve function and red blood cell formation → Deficiency causes Pernicious anaemia

Correct Answer: Option 3 – Vitamin B₁₂ → Aids nerve function and red blood cell formation → Deficiency causes Pernicious anaemia
Vitamin B₁₂ (Cobalamin) is essential for: nerve function (formation of myelin sheath around nerve fibres ); production of red blood cells ( haematopoiesis in bone marrow); DNA synthesis. Deficiency causes Pernicious anaemia — a condition where the body cannot absorb B₁₂ due to lack of intrinsic factor (produced by stomach), leading to megaloblastic anaemia and neurological damage. This combination is entirely correct.
Option 1 (Vitamin A/Calcium/Scurvy): WRONG. Vitamin A (Retinol) regulates vision pigments (rhodopsin); its deficiency causes Night blindness (not Scurvy). Calcium absorption is promoted by Vitamin D. Scurvy is caused by Vitamin C deficiency.
Option 2 (Vitamin D/Vision/Pellagra): WRONG. Vitamin D promotes calcium absorption and bone formation; it does NOT regulate vision. Pellagra is caused by Vitamin B₃ (Niacin) deficiency, not Vitamin D. Vitamin D deficiency causes Rickets (children) and Osteomalacia (adults).
Option 4 (Vitamin C/Blood clotting/Night blindness): WRONG. Vitamin C (Ascorbic acid) is an antioxidant and essential for collagen synthesis; its deficiency causes Scurvy. Blood clotting is supported by Vitamin K. Night blindness is caused by Vitamin A deficiency.
SSC Selection Post 2025 (Phase XIII) – 31 July 2025 Shift 3 · Balanced diet and roughage

Q72. Read the following two statements carefully and choose the correct option:
Statement 1: Poor nutrition among adolescents can result in stunted growth and deficiency diseases.
Statement 2: Proper diet plays a critical role in the healthy development of adolescents.

  1. (a) Only 1
  2. (b) Only 2
  3. (c) Both 1 and 2 are correct
  4. (d) Neither 1 nor 2 is correct
Answer & solution

Answer: (c) Both 1 and 2 are correct

Correct Answer: Option 3 – Both 1 and 2 are correct
Statement 1 (TRUE): Poor nutrition during adolescence can indeed result in stunted growth (linear growth faltering due to insufficient protein, calories, zinc, and other micronutrients), as well as deficiency diseases — iron deficiency anaemia , Vitamin D deficiency (rickets/weak bones), iodine deficiency disorders, Vitamin A deficiency (night blindness), etc. Adolescence is a critical period of rapid growth and development requiring adequate nutrition.
Statement 2 (TRUE): A balanced, proper diet provides essential macronutrients (proteins, carbohydrates, fats) and micronutrients (vitamins, minerals) that are critical for healthy physical growth, brain development, hormonal changes, immune function, and overall well-being during adolescence. Both statements are factually accurate and well-supported by nutritional science.
Both statements correctly describe the importance of nutrition for adolescent health.
SSC Selection Post 2025 (Phase XIII) – 24 July 2025 Shift 2 · Nutrition in animals (amoeba, ruminants)

Q73. Which of the following statements correctly describes how unicellular organisms obtain their food?

  1. (a) All unicellular organisms use a mouth-like structure for food intake
  2. (b) Unicellular organisms like Amoeba use pseudopodia, while Paramecium uses cilia to direct food into a fixed spot
  3. (c) Unicellular organisms such as Amoeba and Paramecium absorb food randomly from all over the cell surface
  4. (d) Unicellular organisms digest food externally before taking it into their bodies
Answer & solution

Answer: (b) Unicellular organisms like Amoeba use pseudopodia, while Paramecium uses cilia to direct food into a fixed spot

Correct Answer: Option 2 – Amoeba uses pseudopodia; Paramecium uses cilia to direct food into a fixed spot
Amoeba captures food (bacteria, algae) by engulfing it using pseudopodia (false feet) — extensions of the cell membrane — in a process called phagocytosis. Paramecium has a specialized oral groove with cilia that beat to direct food particles toward the cytostome (a fixed 'mouth-like' spot), where food is ingested into food vacuoles.
Option 1 (All use mouth-like structure): Incorrect; Amoeba has no fixed mouth — it uses pseudopodia and can ingest from any point on the surface.
Option 3 (Both absorb randomly): Incorrect; Paramecium has a defined oral groove — it does not absorb randomly.
Option 4 (External digestion): External digestion is a feature of some fungi and bacteria; not Amoeba or Paramecium.
RRB NTPC GL CBT-1 2024-25 – 24 June 2025 Shift 1 · Balanced diet and roughage

Q74. Which statement is true regarding a balanced diet?

  1. (a) It contains all nutrients in appropriate proportions.
  2. (b) It includes only fruits and vegetables.
  3. (c) It consists mainly of carbohydrates for energy.
  4. (d) It must exclude fats to prevent diseases.
Answer & solution

Answer: (a) It contains all nutrients in appropriate proportions.

RRB NTPC GL CBT-1 2024-25 – 19 June 2025 Shift 2 · Minerals - sources, functions and deficiency

Q75. Deficiency of which nutrient is most directly linked to reduced oxygen-carrying capacity of blood?

  1. (a) Vitamin A
  2. (b) Calcium
  3. (c) Iron
  4. (d) Iodine
Answer & solution

Answer: (c) Iron

RRB NTPC GL CBT-1 2024-25 – 17 June 2025 Shift 2 · Digestive enzymes and juices

Q76. Which enzyme, secreted by the chief cells of the stomach, is crucial for initiating the digestion of proteins?

  1. (a) Amylase
  2. (b) Gastric lipase
  3. (c) Trypsinogen (converted to trypsin)
  4. (d) Pepsinogen (converted to pepsin)
Answer & solution

Answer: (d) Pepsinogen (converted to pepsin)

RRB NTPC GL CBT-1 2024-25 – 17 June 2025 Shift 1 · Vitamins - sources, functions and deficiency

Q77. Deficiency of which vitamin in the diet is most commonly linked to poor vision in dim light (night blindness)?

  1. (a) Vitamin B12
  2. (b) Vitamin D
  3. (c) Vitamin C
  4. (d) Vitamin A
Answer & solution

Answer: (d) Vitamin A

RRB NTPC GL CBT-1 2024-25 – 13 June 2025 Shift 3 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q78. Which of the following organisms exhibits both autotrophic and heterotrophic modes of nutrition?

  1. (a) Paramecium
  2. (b) Amoeba
  3. (c) Euglena
  4. (d) Plasmodium
Answer & solution

Answer: (c) Euglena

RRB NTPC GL CBT-1 2024-25 – 13 June 2025 Shift 2 · Balanced diet and roughage

Q79. What is the primary reason that roughage is included in a balanced human diet?

  1. (a) It increases sugar absorption.
  2. (b) It aids digestion and prevents constipation.
  3. (c) It builds muscles.
  4. (d) It helps in fat storage.
Answer & solution

Answer: (b) It aids digestion and prevents constipation.

RRB NTPC GL CBT-1 2024-25 – 6 June 2025 Shift 1 · Absorption and assimilation

Q80. A patient lacking bile production would suffer from deficiency in absorption of ______.

  1. (a) fat-soluble vitamins
  2. (b) amino acids
  3. (c) glucose
  4. (d) water
Answer & solution

Answer: (a) fat-soluble vitamins

RRB NTPC GL CBT-1 2024-25 – 5 June 2025 Shift 2 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q81. In holozoic nutrition, the first essential step for complex organisms is ______.

  1. (a) assimilation
  2. (b) ingestion
  3. (c) absorption
  4. (d) egestion
Answer & solution

Answer: (b) ingestion

RRB Technician Grade III 2024-25 – 30 December 2024 Shift 2 · Nutrients - carbohydrates, proteins, fats

Q82. What is the simple form of protein?

  1. (a) Glucose
  2. (b) Glycerol
  3. (c) Amino acid
  4. (d) Fatty acid
Answer & solution

Answer: (c) Amino acid

Correct Answer: Option 3 — Amino acid
Proteins are large, complex biomolecules built from repeating units called amino acids joined by peptide bonds. Therefore the simplest form — the monomer — of a protein is an amino acid. There are 20 standard amino acids, of which 9 are essential and must come from the diet.
In the human body, protein digestion begins in the stomach, where pepsin (activated by HCl) breaks proteins into peptones. In the small intestine trypsin of the pancreatic juice and erepsin/peptidases of the intestinal juice finish the job, converting proteins completely into amino acids, which are then absorbed by the villi into the blood and used for growth and repair of tissues.
❌ Why the other options are incorrect
✗ Glucose — the simplest form of carbohydrate; starch is digested by amylase into glucose, the body's main energy fuel.
✗ Glycerol — along with fatty acids, an end product of fat (lipid) digestion by lipase, not of protein.
✗ Fatty acid — also a digestion product of fats, formed after bile emulsifies them; it is not a protein unit.
📌 SSC & Railway Exam Facts
• End products — Carbohydrate → glucose; Protein → amino acids; Fat → fatty acids + glycerol.
• Kwashiorkor and marasmus are deficiency diseases caused by lack of protein.
• Proteins are called body-building foods; pulses, milk, eggs, fish and soyabean are rich sources.
• Enzymes and most hormones (e.g. insulin) are proteins; haemoglobin is a protein containing iron.
• Proteins contain C, H, O and N (and often S) — nitrogen is what distinguishes them from carbohydrates and fats.
RRB Technician Grade III 2024-25 – 30 December 2024 Shift 2 · Digestive enzymes and juices

Q83. Select the INCORRECT pair related to digestive glands and their enzymes.

  1. (a) Pancreas – pancreatic juice
  2. (b) Liver – bile juice
  3. (c) Gastric gland – pepsin
  4. (d) Salivary gland – trypsin
Answer & solution

Answer: (d) Salivary gland – trypsin

Correct Answer: Option 4 — Salivary gland – trypsin
The salivary glands secrete saliva, whose enzyme is salivary amylase (ptyalin). It acts in the mouth on starch and breaks it into maltose (sugar). Trypsin is not a salivary enzyme at all — it is a protein-digesting enzyme of the pancreatic juice, secreted by the pancreas and active in the small intestine in an alkaline medium. So this pair is wrong.
The main digestive glands are the salivary glands, gastric glands, liver, pancreas and intestinal glands. Together their secretions convert carbohydrates to glucose, proteins to amino acids, and fats to fatty acids and glycerol, which are then absorbed by the villi of the small intestine.
❌ Why the other options are incorrect
✗ Pancreas – pancreatic juice — correct; the pancreas pours pancreatic juice containing trypsin, amylase and lipase into the duodenum.
✗ Liver – bile juice — correct; the liver, the largest gland of the body, makes bile (stored in the gall bladder), which emulsifies fat and makes the medium alkaline.
✗ Gastric gland – pepsin — correct; gastric glands of the stomach secrete pepsin, HCl and mucus; pepsin digests protein in an acidic medium.
📌 SSC & Railway Exam Facts
• HCl makes the stomach medium acidic (pH ≈ 1.5–2) and activates pepsinogen into pepsin; mucus protects the stomach lining.
• Bile contains no enzyme; it only emulsifies fats into small droplets.
• Pancreas is a dual (hetero-crine) gland — it also secretes insulin and glucagon.
• Most digestion and absorption occur in the small intestine, the longest part of the alimentary canal.
• Amylase → starch; Pepsin/Trypsin → protein; Lipase → fat.
RRB Technician Grade III 2024-25 – 29 December 2024 Shift 1 · Digestive enzymes and juices

Q84. Gastric glands present in the wall of the stomach do NOT release:

  1. (a) saliva
  2. (b) pepsin
  3. (c) mucus
  4. (d) hydrochloric acid
Answer & solution

Answer: (a) saliva

Correct Answer: Option 1 — saliva
Saliva is not secreted by the stomach at all. It is produced by the three pairs of salivary glands in the buccal cavity (mouth) — parotid, submandibular and sublingual. Saliva contains the enzyme salivary amylase (ptyalin), which begins the digestion of starch into maltose in the mouth itself.
The gastric glands in the stomach wall release gastric juice, which has exactly three components:
• Hydrochloric acid (HCl) — makes the medium acidic (pH about 1.5–2), kills germs and activates pepsinogen.
• Pepsin — the protein-digesting enzyme, active only in acidic medium.
• Mucus — protects the inner lining of the stomach from the acid and from self-digestion.
❌ Why the other options are incorrect
✗ Pepsin — it IS released by gastric glands; secreted as inactive pepsinogen, converted to active pepsin by HCl, and it breaks proteins into peptones.
✗ Mucus — it IS released by the gastric glands; without it the acid would cause ulcers in the stomach wall.
✗ Hydrochloric acid — it IS released by the oxyntic (parietal) cells of the gastric glands and gives the stomach its acidic medium.
📌 SSC & Railway Exam Facts
• The stomach is the widest part of the alimentary canal; it is J-shaped.
• Salivary amylase works best in a slightly alkaline medium; pepsin works best in an acidic medium.
• Trypsin (pancreatic juice) and erepsin (intestinal juice) also digest proteins, but in the alkaline small intestine.
• Excess HCl causes acidity and peptic ulcers; Helicobacter pylori bacteria are a common cause of ulcers.
• Rennin in the gastric juice of infants curdles milk protein (casein).
RRB Technician Grade III 2024-25 – 29 December 2024 Shift 1 · Digestive enzymes and juices

Q85. Protein digesting enzyme pepsin is secreted in the:

  1. (a) duodenum
  2. (b) stomach
  3. (c) ileum
  4. (d) mouth
Answer & solution

Answer: (b) stomach

Correct Answer: Option 2 — stomach
Pepsin is secreted by the gastric glands present in the wall of the stomach. It is released in an inactive form called pepsinogen, which is converted into active pepsin by the hydrochloric acid (HCl) of the gastric juice.
Pepsin is a proteolytic (protein-digesting) enzyme. It breaks large proteins into smaller units called peptones and proteoses. It works only in a strongly acidic medium (optimum pH about 1.5–2), which is exactly why the stomach secretes HCl. The mucus secreted alongside protects the stomach wall from being digested by its own pepsin.
❌ Why the other options are incorrect
✗ Duodenum — the first part of the small intestine; it receives bile (from liver) and pancreatic juice containing trypsin, amylase and lipase, and works in an alkaline medium.
✗ Ileum — the last part of the small intestine, mainly the site of absorption through finger-like villi; it secretes intestinal juice (succus entericus), not pepsin.
✗ Mouth — secretes saliva with salivary amylase (ptyalin), which digests starch, not protein.
📌 SSC & Railway Exam Facts
• Protein digestion: Pepsin (stomach) → Trypsin (pancreas) → Erepsin/peptidases (intestine) → amino acids.
• Pepsin was discovered by Theodor Schwann (1836) — the first animal enzyme to be discovered.
• Bile has no enzyme; it only emulsifies fats and makes the medium alkaline.
• The pancreas is a mixed gland — exocrine (pancreatic juice) and endocrine (insulin, glucagon).
• Rennin curdles milk in infants; lipase digests fats into fatty acids and glycerol.
RRB Technician Grade III 2024-25 – 28 December 2024 Shift 1 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q86. Which of the following organisms show a parasitic nutritive strategy?

  1. (a) Orchids
  2. (b) Mosses
  3. (c) Acacia
  4. (d) Cuscuta
Answer & solution

Answer: (d) Cuscuta

Correct Answer: Option 4 — Cuscuta
Cuscuta (Amarbel / dodder) is a total stem parasite. It has no chlorophyll and cannot make its own food, so it twines around a host plant and pushes special sucking roots called haustoria into the host's vascular bundles. Through these it draws water, minerals and readymade food, weakening and often killing the host.
This is parasitic nutrition, a type of heterotrophic nutrition in which an organism lives on or inside another living organism and takes its food from it, harming the host in the process.
❌ Why the other options are incorrect
✗ Orchids — most are epiphytes; they only grow *on* a tree for support and make their own food, so they are not parasites.
✗ Mosses — small green bryophytes with chlorophyll; they are autotrophs that photosynthesise their own food.
✗ Acacia (babool) — a normal green tree with leaves and chlorophyll; a complete autotroph.
📌 SSC & Railway Exam Facts
• Heterotrophic nutrition is of three kinds — holozoic, saprophytic and parasitic.
• Rafflesia is a total root parasite and bears the largest flower in the world.
• Mistletoe (Viscum) is a partial stem parasite as it has chlorophyll.
• Pitcher plant (Nepenthes) and Venus flytrap are insectivorous plants that trap insects for nitrogen.
• Lichen shows symbiosis between an alga and a fungus.
RRB Technician Grade III 2024-25 – 28 December 2024 Shift 1 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q87. Select the parasitic plant from the given options.

  1. (a) Cucumber
  2. (b) Cuscuta
  3. (c) Cabbage
  4. (d) Cactus
Answer & solution

Answer: (b) Cuscuta

Correct Answer: Option 2 — Cuscuta
Cuscuta, known in India as Amarbel, is a yellow, thread-like climbing plant that has no chlorophyll and almost no leaves. Being unable to photosynthesise, it lives as a total parasite: it coils around the stem of a host plant and sends haustoria — special sucking roots — into the host's xylem and phloem to draw water, minerals and prepared food.
This is parasitic nutrition, a form of heterotrophic nutrition. The host plant gradually becomes weak, its growth is stunted and it may finally die, which is why Cuscuta is treated as a serious weed.
❌ Why the other options are incorrect
✗ Cucumber — a green autotrophic climber (creeper) that makes its own food by photosynthesis.
✗ Cabbage — a green leafy vegetable full of chlorophyll; a complete autotroph.
✗ Cactus — a xerophyte of deserts; its green stem (phylloclade) does the photosynthesis while leaves are reduced to spines.
📌 SSC & Railway Exam Facts
• Cuscuta is a total stem parasite; Rafflesia is a total root parasite.
• Mistletoe (Viscum) and Sandalwood (Santalum) are partial parasites.
• Pitcher plant (Nepenthes) is insectivorous, getting nitrogen from insects.
• Fungi growing on bread and pickles are saprophytes.
• In lichen an alga and a fungus live together in symbiosis; Rhizobium in root nodules of legumes is also symbiotic.
RRB Technician Grade III 2024-25 – 28 December 2024 Shift 2 · Human digestive system - organs

Q88. Which of the following is the longest part of the alimentary canal?

  1. (a) Small intestine
  2. (b) Large intestine
  3. (c) Food pipe
  4. (d) Stomach
Answer & solution

Answer: (a) Small intestine

Correct Answer: Option 1 — Small intestine
The small intestine is the longest part of the alimentary canal, measuring about 6 to 7 metres in an adult human. It is highly coiled so that this great length fits into the abdominal cavity. Its three parts are the duodenum, jejunum and ileum.
The small intestine is the site of complete digestion of carbohydrates, proteins and fats — it receives bile from the liver, pancreatic juice from the pancreas and intestinal juice from its own walls. Its inner lining bears millions of finger-like projections called villi, which hugely increase the surface area for absorption of digested food into the blood.
❌ Why the other options are incorrect
✗ Large intestine — only about 1.5 metres long; it absorbs water and salts from the undigested food and forms faeces.
✗ Food pipe (oesophagus) — about 25 cm long; it merely carries the swallowed food from the mouth to the stomach by peristalsis.
✗ Stomach — a J-shaped muscular bag, not the longest part; it churns food and digests protein with pepsin in an acidic medium made by HCl.
📌 SSC & Railway Exam Facts
• The small intestine is longest in herbivores (they digest cellulose) and shorter in carnivores.
• The liver is the largest gland in the body; bile emulsifies fats into small globules.
• Appendix is a vestigial organ attached to the large intestine.
• Salivary amylase (ptyalin) starts starch digestion in the mouth.
• The complete alimentary canal in humans is about 9 metres long.
RRB Technician Grade III 2024-25 – 27 December 2024 Shift 1 · Nutrition in animals (amoeba, ruminants)

Q89. Which of the following helps Paramoecium move food to the specific spot in the cell to obtain nutrition?

  1. (a) Cilia
  2. (b) Pseudopodia
  3. (c) Parapodia
  4. (d) Flagella
Answer & solution

Answer: (a) Cilia

Correct Answer: Option 1 — Cilia
Paramoecium is a unicellular organism that shows holozoic nutrition. Its whole body surface is covered with fine hair-like structures called cilia. The cell has a definite shape and a fixed opening — the oral groove — so food cannot be taken in at any random point.
The rhythmic beating of the cilia creates a water current that sweeps food particles to that specific spot in the cell, where they are engulfed to form a food vacuole. Inside the vacuole, enzymes break the food into simpler substances (digestion); the useful part is absorbed into the cytoplasm and the undigested residue is thrown out.
❌ Why the other options are incorrect
✗ Pseudopodia — the temporary "false feet" of Amoeba, formed by flowing cytoplasm; they are used for movement and to engulf food, but Amoeba has no fixed spot for ingestion.
✗ Parapodia — paired fleshy lateral appendages used for swimming and crawling in annelids such as Nereis; not found in unicellular organisms.
✗ Flagella — long whip-like structures that give locomotion to Euglena and to the sperm; they are far fewer and much longer than cilia.
📌 SSC & Railway Exam Facts
• Nutrition in Amoeba = phagocytosis, using pseudopodia and a food vacuole.
• Paramoecium is called the slipper animalcule; cilia serve both feeding and locomotion.
• Cilia are short and many, flagella are long and few.
• Ingestion → digestion → absorption → assimilation → egestion are the five steps of holozoic nutrition.
• Human trachea is also lined with ciliated epithelium that pushes dust and mucus out.
RRB Technician Grade III 2024-25 – 27 December 2024 Shift 2 · Digestive enzymes and juices

Q90. Which of the following glands secretes trypsin enzyme?

  1. (a) Salivary gland
  2. (b) Gastric gland
  3. (c) Liver
  4. (d) Pancreas
Answer & solution

Answer: (d) Pancreas

Correct Answer: Option 4 — Pancreas
The pancreas is a large gland lying just below the stomach. It secretes pancreatic juice into the duodenum (the first part of the small intestine) through the pancreatic duct. This juice contains trypsin, which digests proteins, amylase, which digests starch, and lipase, which breaks down emulsified fats.
The pancreas is a mixed (hetero-crine) gland — as an exocrine gland it pours digestive enzymes into the gut, and as an endocrine gland its islets of Langerhans release the hormones insulin and glucagon straight into the blood.
❌ Why the other options are incorrect
✗ Salivary gland — secretes saliva containing the enzyme salivary amylase (ptyalin), which begins the digestion of starch in the mouth.
✗ Gastric gland — in the stomach wall; it secretes hydrochloric acid, the protein-digesting enzyme pepsin and protective mucus — but not trypsin.
✗ Liver — the largest gland of the body; it secretes bile, which contains no enzyme and only emulsifies fats and makes the food alkaline.
📌 SSC & Railway Exam Facts
• Trypsin → proteins; Amylase → starch; Lipase → fats — all from pancreatic juice.
• The pancreas is a mixed gland (exocrine + endocrine).
• Pepsin works in an acidic medium, trypsin in an alkaline medium.
• Bile is made in the liver and stored in the gall bladder.
• Final digestion and absorption occur in the small intestine through finger-like villi.
RRB Technician Grade III 2024-25 – 27 December 2024 Shift 3 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q91. Which of the following is/are NOT a parasitic organism?

  1. (a) Ticks
  2. (b) Lice
  3. (c) Cuscuta
  4. (d) Amoeba
Answer & solution

Answer: (d) Amoeba

Correct Answer: Option 4 — Amoeba
A parasite is an organism that lives on or inside another living organism, the host, and derives its food from it while harming the host. This mode of heterotrophic nutrition is called parasitic nutrition.
Amoeba is not a parasite. It is a free-living unicellular protozoan of pond water that shows holozoic nutrition: it engulfs solid food particles by forming pseudopodia (false feet) in a process called phagocytosis, digests them in a food vacuole, absorbs the useful part and throws out the undigested matter anywhere on its surface.
❌ Why the other options are incorrect
✗ Ticks — ectoparasites that cling to the skin of cattle, dogs and humans and suck blood.
✗ Lice — ectoparasites of the human scalp and body that also live by sucking blood.
✗ Cuscuta (Amarbel) — a parasitic plant with no chlorophyll; it twines around a host and sucks sap through haustoria.
📌 SSC & Railway Exam Facts
• Modes of heterotrophic nutrition: holozoic, saprophytic and parasitic.
• Amoeba, Paramecium and human beings show holozoic nutrition.
• Fungi, bread mould (Rhizopus), mushroom and yeast are saprophytes.
• Entamoeba histolytica causes amoebic dysentery; Plasmodium causes malaria.
• Rafflesia is a root parasite; Mistletoe (Viscum) is a partial stem parasite.
RRB Technician Grade III 2024-25 – 27 December 2024 Shift 3 · Modes of nutrition (autotrophic, heterotrophic, parasitic, saprophytic)

Q92. Which of the following processes involves the transfer of a source of energy (food) from outside the body of an organism to inside?

  1. (a) Transportation
  2. (b) Translocation
  3. (c) Nutrition
  4. (d) Metabolism
Answer & solution

Answer: (c) Nutrition

Correct Answer: Option 3 — Nutrition
Nutrition is defined as the process by which an organism takes in food from outside its body, digests it and uses it to obtain energy and materials for growth, repair and maintenance of the body. The food is the organism's source of energy, so its transfer from outside to inside is exactly nutrition.
Nutrition is of two broad kinds. Autotrophic nutrition — green plants prepare their own food by photosynthesis. Heterotrophic nutrition — animals and fungi take ready-made food; it is further of three types, holozoic (Amoeba, humans), saprophytic (fungi) and parasitic (Cuscuta, ticks).
❌ Why the other options are incorrect
✗ Transportation — carrying of substances within the body (blood carrying oxygen and food), not intake from outside.
✗ Translocation — movement of prepared food from leaves to other parts of a plant through the phloem.
✗ Metabolism — the sum of all chemical reactions (anabolism + catabolism) already going on inside the body.
📌 SSC & Railway Exam Facts
• Steps of nutrition: ingestion, digestion, absorption, assimilation and egestion.
• Amoeba shows holozoic nutrition using pseudopodia.
• The five main nutrients are carbohydrates, proteins, fats, vitamins and minerals.
• Photosynthesis occurs in chloroplasts and needs CO₂, water, sunlight and chlorophyll.
• Digestion of starch begins in the mouth by the enzyme salivary amylase (ptyalin).
RRB Technician Grade III 2024-25 – 26 December 2024 Shift 3 · Absorption and assimilation

Q93. Select the correct option related to the function of villi in the small intestine.

  1. (a) Secretion of minerals
  2. (b) Increases absorptive surface area
  3. (c) Protection from acid
  4. (d) Helps in excretion
Answer & solution

Answer: (b) Increases absorptive surface area

Correct Answer: Option 2 — Increases absorptive surface area
The inner lining of the small intestine carries millions of tiny finger-like projections called villi. Their single purpose is to increase the surface area for absorption of the digested food, so that maximum nutrients are taken in during the short time the food stays there.
Each villus is richly supplied with blood capillaries and a lymph vessel (lacteal). Glucose, amino acids, vitamins and minerals pass into the blood capillaries, while fatty acids and glycerol are absorbed by the lacteal. The blood then carries the nutrients to every cell of the body — this is assimilation.
❌ Why the other options are incorrect
✗ Secretion of minerals — minerals are absorbed from food, not secreted by villi; digestive juices are secreted by the glands of the gut wall, liver and pancreas.
✗ Protection from acid — the stomach is protected from HCl by a layer of mucus, not by villi; food entering the small intestine is already made alkaline by bile and pancreatic juice.
✗ Helps in excretion — excretion of nitrogenous waste is done by the kidneys; undigested food is egested through the large intestine and anus, which is not the same as excretion.
📌 SSC & Railway Exam Facts
• The small intestine is the longest part of the alimentary canal (about 6 metres) and the main site of digestion and absorption.
• It has three parts — duodenum, jejunum and ileum; villi are most numerous in the ileum.
• Bile from the liver (stored in the gall bladder) has no enzyme; it emulsifies fat and makes the food alkaline.
• Pancreatic juice contains trypsin (protein), amylase (starch) and lipase (fat).
• The large intestine mainly absorbs water and some salts; the appendix is a vestigial organ.
RRB Technician Grade III 2024-25 – 24 December 2024 Shift 1 · Digestive enzymes and juices

Q94. Select the INCORRECT pair related to digestive glands and their enzymes.

  1. (a) Salivary gland – trypsin
  2. (b) Pancreas – pancreatic juice
  3. (c) Liver – bile juice
  4. (d) Gastric gland – pepsin
Answer & solution

Answer: (a) Salivary gland – trypsin

Correct Answer: Option 1 — Salivary gland – trypsin
The salivary glands in the mouth secrete saliva, whose enzyme is salivary amylase (ptyalin). Ptyalin acts in a slightly alkaline medium and breaks starch down into maltose (sugar), which is why chewed rice or bread slowly begins to taste sweet.
Trypsin, on the other hand, is a protein-digesting (proteolytic) enzyme of the pancreatic juice. It is secreted by the pancreas, poured into the duodenum of the small intestine, and works in an alkaline medium created by bile. Therefore pairing the salivary gland with trypsin is incorrect.
❌ Why the other options are incorrect
✗ Pancreas – pancreatic juice — a correct pair; pancreatic juice contains trypsin (protein), lipase (fat) and pancreatic amylase (starch).
✗ Liver – bile juice — a correct pair; the liver makes bile, which is stored in the gall bladder, makes the medium alkaline and emulsifies fats.
✗ Gastric gland – pepsin — a correct pair; gastric glands of the stomach secrete HCl, pepsin and mucus, and pepsin digests protein in an acidic medium.
📌 SSC & Railway Exam Facts
• There are three pairs of salivary glands — parotid, submandibular and sublingual.
• Bile contains no enzyme; it only emulsifies fat and neutralises the acidic food arriving from the stomach.
• The liver is the largest gland in the human body; the pancreas is the largest mixed gland.
• Final digestion and absorption take place in the small intestine through finger-like projections called villi.
• HCl of the stomach kills germs and keeps the pH at about 1.5–2, which pepsin needs to act.
RRB Technician Grade III 2024-25 – 24 December 2024 Shift 2 · Digestive enzymes and juices

Q95. Which of the following statements is/are correct related to eco-system?
(i) Food we eat is digested by various enzymes in our body.
(ii) Enzyme is specific in their action.
(iii) Specific enzymes are needed for the breakdown of a particular substance.

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

Answer: (b) (i), (ii) and (iii)

Correct Answer: Option 2 — (i), (ii) and (iii)
Enzymes are biological catalysts — proteins that speed up chemical reactions in the body without being used up themselves. All three statements about them are true:
• (i) is correct — the food we eat is digested by a series of enzymes: salivary amylase in the mouth, pepsin in the stomach, and trypsin, lipase and amylase from the pancreas, together with the enzymes of intestinal juice.
• (ii) is correct — every enzyme is specific in its action and fits only one kind of substrate, just as a particular key fits only one lock (the lock-and-key model).
• (iii) is correct — because of this specificity, a separate enzyme is required for each substance: amylase only for starch, pepsin and trypsin for proteins, and lipase for fats.
This specificity is also why non-biodegradable substances survive — no decomposer has an enzyme that fits them.
❌ Why the other options are incorrect
✗ Only (ii) and (iii) — it leaves out (i), which correctly says that our food is digested by various enzymes.
✗ Only (i) and (ii) — it wrongly rejects (iii); specific enzymes are indeed needed for particular substances.
✗ Only (i) — it rejects both (ii) and (iii), although enzyme specificity is a basic and well-established fact.
📌 SSC & Railway Exam Facts
• Enzymes are mostly proteins; they work best at body temperature (about 37 °C) and at a specific pH.
• Pepsin needs an acidic medium (stomach), while trypsin needs an alkaline medium (small intestine).
• Salivary amylase (ptyalin) converts starch → maltose; lipase converts fat → fatty acids + glycerol.
• High temperature denatures enzymes and destroys their activity permanently.
• Bile contains no enzyme; it only emulsifies fat and makes the medium alkaline for pancreatic enzymes.
RRB Technician Grade III 2024-25 – 23 December 2024 Shift 1 · Digestive enzymes and juices

Q96. In the digestive system, which of the following releases hydrochloric acid, a protein digesting enzyme called pepsin, and mucus?

  1. (a) Gall bladder
  2. (b) Gastric glands
  3. (c) Salivary glands
  4. (d) Pancreas
Answer & solution

Answer: (b) Gastric glands

Correct Answer: Option 2 — Gastric glands
The gastric glands are present in the wall of the stomach and secrete the gastric juice, which has three components:
• Hydrochloric acid (HCl) — makes the medium acidic, kills germs entering with food and activates the enzyme.
• Pepsin — a protein-digesting enzyme that works only in an acidic medium and breaks proteins into peptones.
• Mucus — a slimy layer that protects the inner lining of the stomach from the corrosive action of its own acid.
If mucus is not secreted properly, the acid injures the stomach wall and causes acidity and peptic ulcers.
❌ Why the other options are incorrect
✗ Gall bladder — only stores and concentrates bile made by the liver; bile is alkaline and has no enzymes.
✗ Salivary glands — secrete saliva containing salivary amylase (ptyalin), which digests starch in the mouth in an alkaline medium.
✗ Pancreas — secretes pancreatic juice with trypsin (proteins), amylase (starch) and lipase (fats); it also makes insulin.
📌 SSC & Railway Exam Facts
• Gastric juice is acidic (pH about 1.5–2); HCl is secreted by the oxyntic (parietal) cells.
• Pepsin is secreted in an inactive form called pepsinogen, activated by HCl.
• The liver is the largest gland in the body; the pancreas is a mixed gland (exocrine + endocrine).
• Bile does not digest, it only emulsifies fats and makes the medium alkaline for pancreatic enzymes.
• Absorption of digested food occurs mainly in the small intestine through the villi.
RRB Technician Grade III 2024-25 – 23 December 2024 Shift 3 · Digestive enzymes and juices

Q97. When we eat something we like, our mouth waters by a fluid called saliva. In this situation, which enzymes break starch into simple sugar?

  1. (a) Pepsin enzymes
  2. (b) Trypsin enzymes
  3. (c) Pancreatic enzymes
  4. (d) Amylase enzymes
Answer & solution

Answer: (d) Amylase enzymes

Correct Answer: Option 4 — Amylase enzymes
Digestion begins in the buccal cavity (mouth). The three pairs of salivary glands pour out saliva, which contains the enzyme salivary amylase, also called ptyalin. This enzyme breaks the complex carbohydrate starch into the simple sugar maltose, so about 30 per cent of starch digestion is finished before the food is even swallowed.
Saliva also moistens and lubricates the food so that the tongue can roll it into a bolus for easy swallowing. Saliva works best in a slightly alkaline to neutral medium (pH ≈ 6.8), and its action stops in the acidic stomach.
❌ Why the other options are incorrect
✗ Pepsin enzymes — secreted by the gastric glands of the stomach; pepsin digests proteins into peptones and works only in the acidic medium created by HCl.
✗ Trypsin enzymes — present in the pancreatic juice; trypsin acts on proteins in the alkaline medium of the small intestine, not on starch in the mouth.
✗ Pancreatic enzymes — these (pancreatic amylase, trypsin, lipase) act in the small intestine, not in the mouth where the question places the action.
📌 SSC & Railway Exam Facts
• Ptyalin is the salivary amylase of humans; starch → maltose.
• Largest gland of the human body — the liver; it secretes bile, which emulsifies fats.
• The pancreas is a mixed gland — it makes digestive juice as well as insulin.
• Most absorption of digested food occurs in the small intestine through finger-like villi.
• Stomach HCl kills germs and gives the acidic pH that pepsin needs; the mucus lining protects the stomach wall.
RRB Technician Grade III 2024-25 – 20 December 2024 Shift 2 · Human digestive system - organs

Q98. Which of the following is the correct order of movement of food in the digestive tract?

  1. (a) Oesophagus - Stomach - Mouth
  2. (b) Mouth - Stomach - Oesophagus
  3. (c) Mouth - Oesophagus - Stomach
  4. (d) Oesophagus - Mouth - Stomach
Answer & solution

Answer: (c) Mouth - Oesophagus - Stomach

Correct Answer: Option 3 — Mouth - Oesophagus - Stomach
Food travels through the alimentary canal in a fixed order:
• Mouth (buccal cavity) — teeth chew the food and salivary amylase (ptyalin) in saliva begins the digestion of starch.
• Oesophagus (food pipe) — carries the bolus down to the stomach by wave-like muscular contractions called peristalsis.
• Stomach — gastric glands release HCl, pepsin and mucus; HCl makes the medium acidic and kills germs, pepsin digests proteins, and mucus protects the stomach lining.
After the stomach the food goes to the small intestine → large intestine → rectum → anus.
❌ Why the other options are incorrect
✗ Oesophagus - Stomach - Mouth — digestion cannot begin in the oesophagus, and food never returns to the mouth.
✗ Mouth - Stomach - Oesophagus — the oesophagus lies before the stomach, not after it.
✗ Oesophagus - Mouth - Stomach — food enters the body through the mouth first, not the oesophagus.
📌 SSC & Railway Exam Facts
• Complete path: Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Rectum → Anus.
• Small intestine is the main site of digestion and absorption; it is the longest part (about 6 m) and has finger-like villi to increase surface area.
• Liver secretes bile, which emulsifies fats; bile is stored in the gall bladder.
• Pancreatic juice contains trypsin (protein), amylase (starch) and lipase (fat).
• Large intestine mainly absorbs water; the appendix is a vestigial organ attached to it.
RRB Technician Grade III 2024-25 – 20 December 2024 Shift 3 · Absorption and assimilation

Q99. Select the correct option related to the function of villi in the small intestine.

  1. (a) Secretion of minerals
  2. (b) Increases absorptive surface area
  3. (c) Helps in excretion
  4. (d) Protection from acid
Answer & solution

Answer: (b) Increases absorptive surface area

Correct Answer: Option 2 — Increases absorptive surface area
The inner lining of the small intestine has millions of tiny finger-like projections called villi. Their main job is to increase the surface area for absorption of digested food. A larger surface means much more food can be absorbed in the same length of intestine.
Each villus is richly supplied with blood capillaries and a lymph vessel (lacteal). Glucose and amino acids pass into the blood capillaries, while fatty acids and glycerol are absorbed by the lacteal. The absorbed food is then carried by blood to every cell of the body, where it is used for energy, growth and repair.
❌ Why the other options are incorrect
✗ Secretion of minerals — minerals are absorbed from food, not secreted by villi; digestive juices are secreted by glands, not villi.
✗ Helps in excretion — excretion of nitrogenous waste is done by the kidneys; undigested food is removed by the large intestine and anus.
✗ Protection from acid — the stomach wall is protected from HCl by mucus, not by villi; the acidic food entering the duodenum is neutralised by alkaline bile and pancreatic juice.
📌 SSC & Railway Exam Facts
• The small intestine is the longest part of the alimentary canal (about 6–7 m) and the main site of digestion and absorption.
• It receives bile from the liver, pancreatic juice from the pancreas and intestinal juice from its own walls.
• Bile does not contain enzymes; it makes the medium alkaline and emulsifies fats.
• Trypsin digests proteins and lipase digests fats in the pancreatic juice.
• The large intestine mainly absorbs water; vitamin K and B₁₂ are also produced there by bacteria.

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