Why do snake skin falls off?

The reason why snakes skin (its called shedding) fall of is because

other persons answer

Snakes skin will only stretch a small amount so, periodically, a snake sheds its old skin, having formed a new skin underneath. Young snakes shed much more frequently than older snakes as they grow faster when they're young.

my answer

The primary reason for this (snakes shedding there skin) is that the snakes grows, as the snake grows the outer skin douse not grow so the snake sheds its skin.

HOW?

the snake first rubs its nose against a hard surface the snake hooks its old skin on a twig then slides out of its old skin leaving it in one piece