The _________ prevents the sun's harmful rays from reaching the earth's surface.

Camels,snakes, lizards, many insects, sand are the things we can see in the ___________.

A typical _________ ecosystem contains fish, frogs, algae, waterlilies and other species.

The narrow zone where the lithosphere, hydrosphere and atmosphere meet and interact is called the _________.

The non- living components such as land, water and air which make up our environment is called _________ environment.

Without the __________ our earth would have been barren like the other planets.

The atmosphere is held to the earth by the _________.

The evolution of human beings was due to the changes in the ___________.

The different sources of water such as oceans, seas, bays, lakes, rivers etc form the ___________.

Water is found in _______ states.