Question

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

Assertion (A): Teesta river was earlier a tributary of Ganga now it is a tributary of Brahmaputra.

Reason (R): River capturing is a major feature of Himalayan rivers.

Select the correct answer using the codes given below.

1. Both (A) and (R) are true and (R) is correct explanation of (A)
2. Both (A) and (R) are true, but (R) is not correct explanation of (A)
3. (A) is true, but (R) is false
4. (A) is false, but (R) is true

Answer 1

Correct Answer - Option 1 : Both (A) and (R) are true and (R) is correct explanation of (A)

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

• Teesta river 
  • It originates from the Pahunri glacier.
  • It flows southward through gorges and rapids in the Sikkim Himalaya.
  • It is fed by rivulets arising in the Thangu, Yumthang and Donkha mountain ranges.
  • In Bangladesh, the Teesta joins the Brahmaputra on its right bank, from where the river is known as the Yamuna.
  • Then, it finally merges with the river Padma, which falls in the Bay of Bengal.
• Old records and maps written and drawn by Major James Reynold, the then surveyor-general of India, indicate that the Teesta used to take a different route and flow into the Ganga, instead of merging with the Padma in Bangladesh, as it does now. Hence, Assertion (A) is correct.
• The course of the river had gradually shifted eastwards, owing to neo-tectonic activities in the whale back-shaped plate of the region.
• River capturing is a major feature of Himalayan rivers. River capturing is mainly caused by the headward erosion of the river (which joins and captures the water of its neighbouring stream) and is very common in hilly regions like the Himalayas.  Hence, Reason (R) is correct.
•  Both (A) and (R) are true and (R) is correct explanation of (A).