Fast Evolution Affects Everyone, Everywhere. 1  Dec. 6, 2016 â Rapid evolution of other species happens all around us all the time -- and many of the most extreme examples are associated with human ...
Hair is simple in structure, but has important functions in social functioning. Hair is made of a tough protein called keratin. A hair follicle anchors each hair into the skin. The hair bulb forms the base of the hair follicle. In the hair bulb, living cells divide and grow to build the hair shaft.
How hair grows. Hair grows out of little pockets in your skin, called follicles. Here's how it happens: 1  Your hair begins growing from a root in the bottom of the follicle. The root is made up of cells of protein.  Blood from the blood vessels in your scalp feeds the root, which creates more cells and makes the hair grow.