The early humans way of life made it impossible for them to live in which kind of shelter?

a.) rock shelters in cliffs
b.) tents
c.) permanent homes
d.) caves

For their way of living before, the early humans cannot dwell in permanent homes. Thus, the answer to this question is letter C. This is because it was essential for them to move from one place to another because they were just dependent on the natural abundance of the source of food in a certain area. 

The first one is russia because in russia they were on the rough times and they never had a way to get out of