RAS question
Evapotranspiration in the water cycle refers to:
Correct answer: (B) Combined water loss from evaporation (from surfaces) and transpiration (from plants).
Evapotranspiration is the combined loss of water through evaporation from soil or water surfaces and transpiration from plants.
Explanation
Evapotranspiration matters because it joins two linked movements of water back to the atmosphere. Evaporation changes water on exposed soil or water surfaces into vapour, while transpiration is the release of water from plants, especially through tiny openings in their leaves. The USGS water-cycle diagram explains the term as evaporation plus transpiration: plants lose water from their leaves, and water also evaporates from the soil around them. That is why option B is broader and more accurate than answers that isolate only plants or only oceans. In the land part of the water cycle, this combined process accounts for about 60% of precipitation that falls on land, and it varies with temperature, humidity, wind and vegetation type.
Why the other options are wrong
- (A) Groundwater seepage into oceans describes submarine groundwater discharge, not the return of water to the air by evaporation and plant transpiration.
- (C) Only plant transpiration is too narrow, because evapotranspiration also includes evaporation from soil and other exposed surfaces around plants.
- (D) Only evaporation from oceans misses the plant-transpiration part and the land-surface evaporation included in evapotranspiration.
Concept
This tests water-cycle terminology in basic hydrology: RAS questions often turn on distinguishing similar process terms rather than memorising a diagram. Evapotranspiration recurs because it links climate, vegetation and surface water balance in one concept.