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UPSC CSE CSAT 2025 · Question 52 · Reading comprehension

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

Directions for the following 4 (four) items: Read the following two passages and answer the items that follow the passages. Your answer to these items should be based on the passages only.

Passage—1

It is hard to predict how changes in the climate and the atmosphere’s chemistry will affect the prevalence and virulence of agricultural diseases. But there is a risk that such changes will make some plant infections more common in all climatic zones, perhaps catastrophically so. Part of the problem is that centuries of selective breeding have refined the genomes of most high-value crops. They are spectacular at growing in today’s conditions but genetic variations that are not immediately useful to them have been bred out. This is good for yields but bad for coping with changes. A minor disease or even an unknown one could suddenly rampage through a genetically honed crop.

CSAT 2025 · Q52

Reading comprehension Hard

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

  1. I.Global climate change can result in the migration of several plant diseases to new areas.
  2. II.Scientific understanding of the wild relatives of our present crops would enable us to strengthen food security.

Which of the above assumptions is/are valid?

Answer & explanation

Answer: (c) Both I and II

UPSC's official answer: (c) · the answer UPSC accepted, and the one that counts in the exam

Also defensible: (a)

  • Assumption I is valid: the passage warns that climate change may make some plant infections 'more common in all climatic zones', which presupposes diseases reaching areas where they were rare.
  • Assumption II names two things the passage never mentions: the 'wild relatives' of crops and 'food security'. The passage speaks only of refined crop genomes from which 'genetic variations that are not immediately useful to them have been bred out', which is 'bad for coping with changes'.
  • UPSC's key accepts II as what the argument presupposes: if bred-out variation is what crops need to cope, then understanding where that variation survives, in the wild relatives, would protect crops, which is food security. That gives (c).
  • The directions say to answer 'based on the passages only'; on that strict reading II is an outside inference rather than an assumption of the passage, and only I stands, giving (a).

UPSC's key is (c); a passage-only reading gives (a). In the exam, follow UPSC's broader reading of 'assumption' as what the argument presupposes, even when the option supplies the missing noun.

This box is Minimalist IAS's analysis, with its sources; it does not change UPSC's answer.

The passage warns that climate change may make some plant infections 'more common in all climatic zones', which implies diseases reaching areas where they were rare, so I is assumed. It then blames crops' vulnerability on genetic variations that 'have been bred out'; the argument takes for granted that this lost variation, which survives in the crops' unrefined wild relatives, is what would let crops cope with change, so II is also valid: (c).

  • ✓ I The passage warns that climate change may make some plant infections 'more common in all climatic zones', which implies diseases spreading into areas where they were not common before.
  • ✓ II The author's claim that breeding out variation is 'bad for coping with changes' assumes that such variation is what gives resilience. The variation bred out of refined crops survives in their wild relatives, so the argument presupposes that understanding them would help crops withstand disease, which is what protecting food security means here.

Remember · When a passage blames a problem on something lost (genetic variation), UPSC treats an assumption about recovering it from its source as valid, even if the source is named only in the option.

Question and answer: UPSC's official GS Paper II (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). ·

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