Question

why do you think that mountains have a scanty population

Answer 1

yes I think
it's right

Answer 2

1. Mountains have striking topographic relief making it very difficult for people to establish connectivity. Roads,telephone lines,railways are very less developed at such areas.
2. They are not suitable for cultivation or industry setup for two reasons. The first being their harsh geographic profile  while the other is for these to flourish,amenities like electricity,water supply,connectivity and on top of that manpower is required which are again scarce.
3. Lack of oxygen with altitude is a concern making people prone to severe breathing problems,fatigue and abnormal blood pressure.
4. Lack of proper exposure to sunlight gives way to vitamin deficiencies and related illness.