Question

Why are plains and coastal areas densely populated

Answer 1

where ever,extremes of climate occur it can be said thatpopulation density generally tends to be less

Answer 2

Plains are almost low land areas as it having equal elevation, formed along the bottoms of valleys. so, plains are good for agriculture as it's very fertile and good for crop growing.

Coastal areas are the areas on the banks of sea. so , they are highly vegetative and also providing us a rich biological resources like fisheries and a lot of sea foods.

so, people settle down on those area where they get a good survival.