Question

Indo gangetic Plains have high density of population find the reasons

Answer 1

Each and every civilization flourished on tha bank of rives. The same reason stand for indo gangetic plains. Some of them are-
# not difficult terrain (like hilly region, dense forest etc)
# availability of water ( huge network of rives and it's tributaries)
# fertile soil for agricultural (alluvial soils brought by rives)
# availability of water for industrial purpose ( more employment generation)
these all factors affect the population density of a location.

Answer 2

1) This area in south Asia is extremely fertile and excellent for farming.

2) This makes the Indo-Gangetic plain a heaven for Indian farmers to grow rice and wheat.

3) The plain supports high density of population as it is very easy to build on.