Body Movements — Science STD 6 — Question

A snail has a rounded structure on its back called the shell. It is the outer skeleton of the snail but is not made of bones. It helps to protect the snail. The shell is a single unit and does not help in moving from place to place. It has to be dragged along. When a snail crawls, a thick structure and the head of the snail may come out of an opening in the shell. The thick structure is its foot which is made of strong muscles. This foot helps to move.