Hair is the hair on the head and back of the back. In addition to the increase in the beauty of hair, mainly protects the mind. Summer can prevent the scorching sun, winter can be cold. Soft fluffy hair is elastic, can withstand a lighter collision, but also can help head sweat evaporation. The average person's hair is about 100,000 roots. In all hair, the length of the hair is the longest, especially the woman with long hair, some can grow to 90~100cm, even 150cm.