2013 GS Paper I, all questions
UPSC Prelims 2013 · GS Paper I
Question 22: Environment and Ecology
In the grasslands, trees do not replace the grasses as a part of an ecological succession because of
ainsects and fungi
blimited sunlight and paucity of nutrients
cwater limits and fire
dNone of the above
AnswerUPSC’s answer is (c).
Natural grasslands persist where water is limited or where fire sweeps through often. Low or seasonal rainfall stops tree seedlings from establishing, and fires kill saplings while grasses regrow from buds protected near the ground. Succession therefore stops at the grass stage and trees do not replace grasses. Insects and fungi, or shortage of sunlight and nutrients, are not the main limits.
Why each option is right or wrong
- (a) Wrong. Insects and fungi are not what holds back trees in grasslands.
- (b) Wrong. Grasslands are open and sunny, and nutrients are not the main limit.
- (c) Correct. Water shortage and fire stop trees from replacing grasses.
- (d) Wrong. Water limits and fire are the answer.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2013, General Studies Paper I, Series A. The paper on upsc.gov.in.