UPSC Prelims 2022 · CSAT

Question 33: Reading Comprehension

Passage beginning “Natural selection cannot anticipate future environments…” — Passage—1 · as printed by UPSC

With reference to the passage, the following assumptions have been made :

1.Only species that have the ability to overcome environmental catastrophes will survive and perpetuate.
2.More than 90% of the species on the earth are in the danger of getting extinct due to drastic changes in the environment.
3.Darwin’s theory explains all the natural phenomena.

Which of the above assumptions is/are valid?

a1 only

b1 and 2 only

c3 only

d1, 2 and 3

AnswerUPSC’s answer is (a).

The passage says species that cannot get through environmental hardship die out, so only those able to survive catastrophes persist (1). It says more than 90% of species that have ever lived are already extinct, which is not the same as saying over 90% of present species are in danger (2). It compares Darwinian laws with the laws of Newton and Einstein as laws explaining natural phenomena, but never claims they explain all natural phenomena (3).

1. Species that cannot survive environmental hardship die out, so only the able persist.
2. The 90% figure is for all species that ever lived and are now extinct, not for present species at risk.
3. Darwinian laws are said to explain natural phenomena, not all of them.

How you could have got this

If you were sure statement 1 is correct, (c) goes: it leaves 1 out.
What you needed to know: Species that cannot survive environmental hardship die out, so only the able persist.
Then, if you were sure statement 2 is not correct, (b) and (d) go: each of them includes 2.
What you needed to know: The 90% figure is for all species that ever lived and are now extinct, not for present species at risk.

Only (a) is left. You didn’t need statement 3.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong

(a) Correct: only assumption 1 is supported.
(b) Wrong: assumption 2 confuses species already extinct with species presently at risk.
(c) Wrong: assumption 3 overstates what Darwinian theory is said to explain.
(d) Wrong: assumptions 2 and 3 are unsupported.

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

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