Question

Why is human hair is not growing in other colors other than black and white and grey?
Also say why hair is thick in mustache but not like in head?

Answer 1

because1) hairs colours can be obtained by melanin in body.melanin is in black and brown colours. if the less melanin present in body the colour of body and hair become white.but not other colours because melanin in black colour.
2)about second question i cant tell.but worry not i will reply fast