Water is found on the Earth’s surface, under the ground and in the atmosphere as water vapour. Maximum amount of water available is marine water which is salty. Most of the fresh water available on the earth is in the form of frozen ice. Water is essential for the survival of plants and animals, as cellular processes take place in a water medium. Substances are transported from one part of the body to the other in a dissolved form. Hence, organisms need to maintain the level of water bodies in order to stay alive.
The availability of water decides not only the number of individuals of each species that are able to survive in a particular are, but it also decides the diversity of life there.
