Growing Up With Ten Thousand Whys: Human Life Volume (Latest Edition)

Author: Li Jie
Publisher:
Publish Date: 2005-11-01
Features: Why don't eyebrows grow as long as hair? Our eyebrows and hair grow every day, but why aren't eyebrows as long as hair? The reason is that the growth rates of eyebrows and hair are different. Each hair on the human body can grow continuously for 2 to 6 years, and then it falls out after about a month. If this hair grows 0.3 millimeters per day, it can reach 66 centimeters in 6 years. However, eyebrows only grow 0.16 millimeters per day, with a growth cycle of only about 2 months. Once they stop growing, they fall out within a few days. That's why eyebrows are always shorter than hair.
There are about 1 million hairs on each person's body, divided into three main categories: First category includes long hairs like hair and beard; the second category includes short hairs like eyebrows and eyelashes; and the third category is body hair. Among these, body hair is the most abundant.
Knowledge Encyclopedia
A person's eyebrows have only a few hundred hairs, and their function is to protect the eyes. They can block sweat and rain flowing from the forehead, as well as falling dust, preventing these things from entering the eyes directly. Eyebrows can also make our expressions more vivid. P6-7