Question

why Mountains are boon for people living in the plains​

Answer 1

The Himalayas act as a boon for India as they act as a barrier to cold siberian winds. They give tropical touch to the climate of India. They stop rear-bearing monsoon winds from crossing into Tibet and force the wids to shed their moisture within Indian- subcontinent.

Answer 2

People live on plains rather than mountains because on plains there is vast level lands rich agricultural resources good ...

....The Himalayas act as a boon for India as they act as a barrier to cold siberian winds. ... They block the rain bearing monsoon winds from the Arabian sea and the bay of Bengal. Therefore, the North Indian plains receive plenty of rainfall. There is a lot of snowfall in the higher regions of the mountains.