Hair growth of human is more on head rather than other parts .Why?

we lose most of the heat in our body's from our heads this is for two reasons the brain uses a lot of energy and heat rises. I'm not sure why we have less hair than apes but I think it has to do with early humans developing clothes so they did not need the hair to keep warm.

as far as pubic hair goes that serves a social function showing that we are sexually mature and not children.

also the hair on our armpits makes for less friction when we swing our arms. a interesting fact is that the more hair a ape has compared with other apes in his tribe the more dominant he is, hair, lots of hair is a sign of dominants