What causes some reddish haired people to have curly black hairs growing out of their scalp with the

Hormones, genetics, what?

What causes some reddish haired people to have curly black hairs growing out of their scalp with the red hair?

Its genetics. The genetic information in some of the cells responsible for the pigmentation[coloring] and shape[straight/curly/wawy] mutate, thus the information they carry changes and they grow different colored hair. This is not only present in redheads, but in any colored hair [though i have never seen it in blondes], darker-haired people tend to grow a couple of gray hairs, which fully lack pigmentation.

Hormones dont have much to do with the hair that grows on our scalps, they influence the darkness and length of the hair on our faces for example[thats why men have moustaches and beards]

What causes some reddish haired people to have curly black hairs growing out of their scalp with the red hair?

god knows

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