Because the skin excretes melanin, which will come out absorb the UV rays from sun and darken the skin, but the hair doesn't, it can only decompound melanin.
Because the skin excretes melanin, which will come out absorb the UV rays from sun and darken the skin, but the hair doesn't, it can only decompound melanin.
答案一，人体会在皮肤表面增加黑色素的沉积，阻挡阳光中的紫外线深入皮肤内层,但是头发没这本事，只会分解黑色素。