SSC Selection Post 2025 (Phase XIII) – 29 August 2025 Shift 2 · Drainage patterns, basins and river terminology
Q101. What is the name of the geographical area from which all precipitation flows into a single river system?
- (a) Plateau
- (b) Drainage basin
- (c) Waterfall zone
- (d) Inland depression
Answer & solution
Answer: (b) Drainage basin
Correct Answer: Option 2 – Drainage basin
A drainage basin (also called a river basin, catchment area, or watershed) is the geographical area from which all surface runoff and precipitation drains into a single river system (including its tributaries). Drainage basins are separated by topographic divides called watersheds/water divides. Examples: the Ganga basin drains ~860,000 sq km into the Bay of Bengal; the Indus basin drains into the Arabian Sea.
Option 1 (Plateau): A plateau is an elevated flat-topped landform; it can contain parts of drainage basins but is not itself a drainage area definition.
Option 3 (Waterfall zone): A waterfall zone describes a geographical region along a river where multiple waterfalls occur (e.g., the fall line in eastern USA); not the same as a drainage basin.
Option 4 (Inland depression): A low-lying inland area that may collect water (endorheic basin — water that doesn't flow to the sea); not the standard term for a river drainage area.
A drainage basin (also called a river basin, catchment area, or watershed) is the geographical area from which all surface runoff and precipitation drains into a single river system (including its tributaries). Drainage basins are separated by topographic divides called watersheds/water divides. Examples: the Ganga basin drains ~860,000 sq km into the Bay of Bengal; the Indus basin drains into the Arabian Sea.
Option 1 (Plateau): A plateau is an elevated flat-topped landform; it can contain parts of drainage basins but is not itself a drainage area definition.
Option 3 (Waterfall zone): A waterfall zone describes a geographical region along a river where multiple waterfalls occur (e.g., the fall line in eastern USA); not the same as a drainage basin.
Option 4 (Inland depression): A low-lying inland area that may collect water (endorheic basin — water that doesn't flow to the sea); not the standard term for a river drainage area.