biological importance

Water is the most important material for living organisms.

(1) Living cells are 70 to 95 percent water.

(2) Much of the environment of the earth is water based (about 75 percent of the earth is covered by water).

(3) Water can exist in all three phases (solid, liquid and gas) and can purify itself in the "water cycle."

(4) Water has a very high specific heat (it retains heat better than most other materials). This is necessary for temperature regulation.

(5) Water is the solvent (medium) for most of the chemical reactions that support live. Without water, these could not take place.