There are many kinds of animals with on this earth. They are the , birds, fish, reptiles and . They differ in size, shape and also in colour.

Mammals have on their bodies and they feed their young ones with milk. Birds have on their bodies and they lay eggs. Fish, reptiles and amphibians too lay eggs.
Mammals and birds live on land, but fish can live only in . Amphibians like can live both on land and in water.

Crocodiles and snakes are . Some reptiles like the crocodiles live both on land and in water. Most snakes can live on land but they can't live in water.