2022 GS Paper I, all questions

UPSC Prelims 2022 · GS Paper I

Question 43: Environment and Ecology

“If rainforests and tropical forests are the lungs of the Earth, then surely wetlands function as its kidneys.” Which one of the following functions of wetlands best reflects the above statement ?

aThe water cycle in wetlands involves surface runoff, subsoil percolation and evaporation.
bAlgae form the nutrient base upon which fish, crustaceans, molluscs, birds, reptiles and mammals thrive.
cWetlands play a vital role in maintaining sedimentation balance and soil stabilization.
dAquatic plants absorb heavy metals and excess nutrients.

AnswerUPSC’s answer is (d).

Kidneys filter blood and remove wastes. Wetlands do the same for water: aquatic plants absorb heavy metals and excess nutrients, and trapped sediments and microbes help break down pollutants, so cleaner water leaves the wetland. Option (d) captures this purifying function. The other options describe the water cycle, the food web or sediment balance, which do not match the kidney analogy.

Why each option is right or wrong
  • (a) This describes the water cycle, not filtration of pollutants.
  • (b) This describes the food base, which is a habitat function.
  • (c) This describes sediment balance and soil stabilisation, not purification.
  • (d) Correct. Absorbing heavy metals and excess nutrients is the kidney-like function.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

Practise this paper timedPrevious questionNext question

Source: UPSC, Civil Services (Preliminary) Examination 2022, General Studies Paper I, Series A. The paper on upsc.gov.in.