Following are the reasons why water is necessary for living organisms:
(i) It provides a medium for various life processes that occur inside the bodies of living organisms.
(ii) It is consumed by plants by the process of photosynthesis.
(iii) It helps in maintaining a constant temperature of the body that may alter because of various metabolic reactions that occur in the body.
(iv) It is a universal solvent and can dissolve various particles that enter the body such as salts and sugars.
(v) It forms the habitat for all aquatic life forms.
(vi) It is one of the key agents in soil formation and serves as the living medium for several different ecosystems.