Water is essential for all forms of life. It contitutes about 65-70% of the body weight of animals and plants. In comparison to other liquids, water has a high specific heat, thermal conductivity , surface tension, dipole moment and dielectric constant , etc. These properties allow water to play a key role in biosphere. The high heat of vaporisation and heat capacity are responsible for moderation of the climate and body temperature of living beings. It is an excellent solvent for transportation of minerals and other nutrients for plant nad animal metabolism. What is also required for photosynthesis in plants which releases `O_(2)` into the atmosphere.
