Why do we need water?

Water is the source of life on Earth. If there were no water on our planet, life would never have originated here. All present creatures on the planet, came out of the water. Man consists 70% percent water. Water is necessary for our body daily in the rate of two liters. Water is needed so that all organs function normally. Without water, a person can live only three days. With very hot weather, and even less. So, water is one of the most necessary elements for human life, any other organism and the whole planet.