Question

why does cold reason people haven't black hair

Answer 1

cold region people do not have black hair. A person can have black hair if there is melatonin in his skin. If there is no melatonin in the skin then they will not have black hair. Melatonin makes the hair black. This is a pigment in human skin which is made in skin in presence of sunlight. But in the cold region sunlight is very low. So there is no melatonin in their skin. So their hair is not black. For the lack of melatonin their hair is brownish.