How Does Hair Grow Back Again After Falling Out?

Hair, like plants and trees, has roots. Hair roots grow in the scalp. If there is nothing wrong with the roots hair can grow back again after it falls out. Hair grows at a rate of two centimetres each month. After two to six years, every hair will be replaced. When hair grows to a certain length, it stops growing and then falls out. A new hair then grows out from the roots to replace it.