Question: Why do we grow hair's on our arms , legs and head eyes eyebrows?

Pip Millington answered on 17 Nov 2016:

Body hair and scalp hair seems to have evolved as a way of keeping our bodies warmer in cold climates but humans have far less body hair than other related species like chimpanzees and orangutans.

Evolution suggests there is a reason why we still have eybrows and eyelids though, maybe because they prevented sweat and dust from getting in the eyes and so our ancestors with eyebrows were less likely to be eaten by predators than those without!