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.
Generally speaking, there are 3 layers, which every hair is made up of. The cuticle is an outside layer. It is flat and thin. The cortex, or the middle layer, is the main part of the hair. It is usually thick and firm. The medulla is a inner layer that goes thinly through the middle of the hair. Letâs have a look at all three layers in more detail. Cuticle. The cuticle is commonly comprised of overlapping scales of about ten layers.