The Alpine vegetation in the western Himalayas is found only up to a height of 3000 metres, while in the eastern Himalayas it is found up to a height of 4000 metres. The reason for this variation in the same mountain range is that

1. eastern Himalayas are higher than western Himalayas
2. eastern Himalayas are nearer to the Equator and sea coast than western Himalayas
3. eastern Himalayas get more monsoon rainfall than the western Himalayas
4. eastern Himalayan rocks are more fertile than the western Himalayan rocks

Explanation

Option (b) is correct

• The height of alpine vegetation (tree line) is mainly controlled by local climate—especially temperature, influenced by latitude and maritime effects. The Eastern Himalaya, being nearer the equator and strongly influenced by moisture from the Bay of Bengal, experiences warmer, more humid conditions, allowing the tree line to extend to higher altitudes. In contrast, the Western Himalaya is relatively colder and drier, so alpine conditions occur at lower elevations.

Answer: (b) The eastern Himalayas are nearer to the Equator and the sea coast than the western Himalayas