UPSC Prelims 2016 · CSAT

Question 67: Reading Comprehension

Passage beginning “An increase in human-made carbon dioxide in…” — Passage-4 · as printed by UPSC

Which among the following is the most logical corollary to the above passage ?

aCarbon dioxide is essential for the survival of microorganisms and plants

bHumans are solely responsible for the release of carbon dioxide into the atmosphere

cMicroorganisms and soil carbon are mainly responsible for the increased plant growth

dIncreasing green cover could trigger the release of carbon trapped in soil

AnswerUPSC’s answer is (d).

The passage says more carbon dioxide spurs plant growth, whose roots rouse soil microbes to break down soil carbon faster and release it back as carbon dioxide. A corollary is that more green cover could trigger the release of the carbon locked in soil. Option (a) says carbon dioxide is essential for microbes, which is not said; (b) blames humans solely, which is too strong; (c) reverses the chain, as plant growth drives the microbes.

Why each option is right or wrong

(a) The passage does not say carbon dioxide is essential for microbes.
(b) 'Solely' is too strong.
(c) Reverses the chain: plant growth stimulates the microbes.
(d) Right: more plant growth could release the carbon trapped in soil.

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

Practise this paper timedPrevious question Next question

Source: UPSC, Civil Services (Preliminary) Examination 2016, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.