It means more intelligent
Children of Kenya have short hair due to pollution in Kenya.
yes
Who knows! But my question is, why do you care? I think it is short hair, btw.
Short :)
Usually short hair is more suitable for running because it is very light and is off of your neck so you won't be as hot. But long hair is not that much heavier but can be on your neck. It is your choice, but if you only care about running faster, go with short hair.