Why do snakes shed their skin?

Answer 1

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.

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.

The snake first rubs its nose against a hard surface, hooks its old skin on a twig, then slides out of its old skin leaving it in one piece.
Snakes shed their skin to grow.

Snake skin doesn't stretch as they grow (like ours does !) Therefore - they shed the old skin when it gets too tight - and the new skin underneath provides extra 'growing room'
The skin does not grow with the snake, so when the snake becomes too large, it does not fit in its skin, and must shed and use larger skin.
Simply because it's not continually renewed as ours is. A snake's skin only stretches a small amount - so it needs to shed periodically to allow itself to grow.
it sheds so it can grow new skin

Answer 2

The outer layer of skin is dead and does not grow with the snake. Periodically, the snake sheds this outer layer so the snake is able to grow.