Have you ever stopped to think about why we have hair? Or maybe, why we have hair in some regions of the body and not others, unlike most other mammals, which have hair (fur) everywhere on their bodies?
Hair is a trait that animals have because it keeps them warm, but humans wear clothes, so our needs for hair are actually quite different. For example, it helps us to evaporate sweat when we're hot.
Hair comes in all different shapes and sizes. Some hair is straight; some is curly. It also comes in different colors and for some, it grows faster and longer than others.
The next time you see a nice head of hair, don't forget to think about the evolutionary questions behind why humans have the hair we do!