2. Living hair cells divide to create new cells every twenty-three to seventy-two hours. That’s faster than any other cells in your body.
3. While a hair is growing, cells move up and out of your follicle fast enough for the stringy strand to lengthen about 6 inches (15 centimeters) per year. Strong, straight hair grows the fastest, and fragile, kinky hair grows the slowest.
4. In ancient Rome 2,000 years ago, women plucked their eyebrows and used hair-removal creams made from tree sap, donkey fat, bat blood, and other strange ingredients.
5. When scientists view hair strands under a microscope, they can tell whether a person smokes cigarettes, drinks alcohol, or takes illegal drugs. They can also tell a person’s ethnic background.