A shell is the hard outside coating found on many animals. Snails have shells that form a spiral that was built up as the snail grew bigger. crabs and turtles have a hard shell that perfectly fits the animal inside. Most animals that have shells can hide inside them if they are scared.
You smell things with your nose. dogs and cats have much better senses of smell than people do. People can only smell very strong smells, like cooking food.
A well is a deep hole that has been dug into the ground to reach water. You can use a bucket on the end of a piece of rope to get to the water, or you can use a pump or windmill to suck the water out.
