Why very often, the roots of greying hair are still black and the rest of the hair is white?

Question

Why very often, the roots of greying hair are still black and the rest of the hair is white?

Answer 1

Hair grows from the root. Long hair is a growth from root to tip. Tip grows first and root last in a single hair strand .The last segment loses pigment last .Root that is freshly developing keeps the pigment.