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RAS question

Assertion (A): Biodiversity hotspots are regions that harbour exceptional concentrations of endemic species but have lost at least 70% of their original habitat. Reason (R): India has four globally recognized biodiversity hotspots: the Himalayas, the Indo-Burma region, the Western Ghats-Sri Lanka, and Sundaland. Select the correct answer:

Correct answer: (B) Both A and R are correct but R is NOT the correct explanation of A..

Biodiversity hotspots are defined by exceptional endemism and severe habitat loss, while India's four recognised hotspots are examples of such regions, not the reason for the definition.

  1. (A)

    Both A and R are correct and R is the correct explanation of A.

  2. (B)

    Both A and R are correct but R is NOT the correct explanation of A.

  3. (C)

    A is correct but R is incorrect.

  4. (D)

    A is incorrect but R is correct.

Explanation

Both statements are correct, but the Reason does not explain the Assertion. A biodiversity hotspot is identified by two criteria: it must have exceptional endemism, stated here as at least 1,500 endemic vascular plant species, and it must have lost at least 70% of its original habitat. The Reason is also correct because India has four global biodiversity hotspots: the Himalayas, Indo-Burma, Western Ghats-Sri Lanka and Sundaland, with the Nicobar Islands included in Sundaland. However, that list only gives Indian examples. It does not explain the defining test of a hotspot, which is based on endemism plus habitat loss. Therefore, both A and R are correct, but R is not the correct explanation of A.

Why the other options are wrong

  • (A) R lists the four Indian hotspots but does not explain the criteria in A, namely exceptional endemism and at least 70% loss of original habitat.
  • (C) R is not incorrect because India is stated to have four globally recognised hotspots: the Himalayas, Indo-Burma, Western Ghats-Sri Lanka and Sundaland.
  • (D) A is not incorrect because the hotspot definition requires both exceptional endemic vascular plant diversity and loss of at least 70% of original habitat.

Concept

This tests the Environment and Ecology concept of biodiversity prioritisation, especially the difference between a definition and an example. It recurs in RAS because hotspots connect species endemism, habitat loss and India's conservation geography in one compact theme.

Source

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