Question

which factors are responsible for sparse population in terrain areas? ​

Answer 1

Answer:

Not many people want to live there.

Explanation:

Terrain often means that moving around and building become more complicated. Many people do not like complication, but prefere the easy option if possible, since that frees resources to do something more productive /pleassant. So unless there is a special beneficial reason to settle in the terrain (like a gold deposit, extra fertile soil etc.) few people will be motivated to settle there.