Q1. [1] medium exam-ready
Assertion (A): Variations are essential for the long-term survival of a species.
Reason (R): If all individuals in a population are identical and the environment changes drastically, the entire population could be wiped out.
- A Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- B Both Assertion (A) and Reason (R) are true, but Reason (R) is NOT the correct explanation of Assertion (A).
- C Assertion (A) is true, but Reason (R) is false.
- D Assertion (A) is false, but Reason (R) is true.
Generated by claude-sonnet-4-6 · 2026-06-26 01:00 · grounding rag
Model Answer
Answer: Option A
Both A and R are true, and R is the correct explanation of A. If all individuals are identical and the environment changes drastically, the entire population would be wiped out, proving variations are essential for long-term survival.
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Explanation
- A is true: Variations help species survive changing environmental conditions.
- R is true: As stated in the passage — "if a population of reproducing organisms were suited to a particular niche and if the niche were drastically altered, the population could be wiped out" unless some variants exist.
- R correctly explains A: The reason why variation is essential is precisely because identical populations have no survivors when the environment changes drastically. The heat-resistant bacteria example from the textbook directly supports this link.
- Do not choose (B) — R is not just a true statement; it directly and logically explains A.
Source: Chapter 7, Section 7.1.1 — The Importance of Variation