1.

Round hair follicles produce straight hair, while oval follicles produce curly hair.

2.

Trichotillomania is a condition in which people pull their hair out. It may be hair on the head or hair in other places, such as the eyebrows or eyelashes.

3.

Before the invention of the hair dryer, it was common for men and women to dry their hair using a vacuum cleaner.

4.

Second to bone marrow, hair is the fastest growing tissue in the human body.

5.

A polar bear's fur is not white. Each hair is a clear hollow tube.