UPSC Prelims 2025 CSAT Paper II · Q62 of 78 Comprehension medium

Passage

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.

With reference to the above passage, the following assumptions have been made : I. Global climate change can result in the migration of several plant diseases to new areas. 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 ?

  1. (a) I only
  2. (b) II only
  3. (c) Both I and II ✓ UPSC's answer
  4. (d) Neither I nor II

Why the answer is (c)

• The passage states that climate and atmospheric changes may make plant infections more common in all climatic zones, implying that diseases can migrate to new areas, validating Assumption I. - It highlights that selective breeding has removed genetic variations from high-value crops, making them vulnerable to new diseases. - The text suggests that the lack of genetic diversity is a problem for coping with changes, implying that restoring this diversity (found in wild relatives) is necessary. - Therefore, understanding and utilizing the genetic potential of wild relatives would help strengthen food security against these threats, validating Assumption II. - Since both assumptions are logically supported by the text's discussion on climate impact and genetic vulnerability, the correct option is (c).

Why the other options are wrong

(a) I only
This option is incorrect because it ignores the validity of Assumption II, which is supported by the passage's emphasis on the need for genetic diversity found in wild relatives to combat disease risks.
(b) II only
This option is incorrect because it ignores the validity of Assumption I, which is directly supported by the passage's statement that climate changes may make infections more common in all climatic zones.
(d) Neither I nor II
This option is incorrect because both assumptions are valid inferences from the passage's discussion on climate-driven disease spread and the necessity of genetic diversity for food security.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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