The Himalayas form source of several large perennial rivers.

Question

Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R).

Assertion (A): The Himalayas form source of several large perennial rivers.

Reason (R): The higher ranges of Himalayas are snow covered throughout the year.

Select the correct answer from the code given below:

1. A. Both (A) and (R) are true, but (R) is not the correct explanation of (A)
2. B. (A) is false, but (R) is true
3. C. (A) is true, but (R) is false
4. D. Both (A) and (R) are true and (R) is the correct explanation of (A) (Correct answer)

Correct Answer

Option D — Both (A) and (R) are true and (R) is the correct explanation of (A)

Detailed Solution & Explanation

The correct answer is Both (A) and (R) are true and (R) is the correct explanation of (A).

Key Points

• Assertion is true. The Himalayas are the source of several great perennial rivers — the Indus, Ganga and Brahmaputra systems and their tributaries.
• Reason is true. The higher ranges of the Himalayas are snow-covered throughout the year, above the permanent snowline.
• (R) explains (A) exactly: the rivers are perennial *because* melting snow and glaciers feed them through the dry season, in addition to the monsoon rain. Hence option (d).

Additional Information

• This is the key contrast with peninsular rivers — the Godavari, Krishna, Kaveri, Mahanadi and Narmada — which are rain-fed and therefore seasonal, shrinking sharply after the monsoon.
• The three Himalayan river systems and their glacial sources:
  • Indus — from near Lake Mansarovar in Tibet
  • Ganga — as the Bhagirathi from the Gangotri glacier; it becomes the Ganga at Devprayag, where it meets the Alaknanda
  • Brahmaputra — as the Tsangpo in Tibet, entering India as the Siang/Dihang
• Himalayan rivers are antecedent in parts — the Indus, Sutlej and Brahmaputra cut through the range in deep gorges because they are older than the mountains they cross.
• The snowline is lower on the southern slopes in the eastern Himalayas because of heavier precipitation, and rises westward.