Why water is so important?

Whithout water there is no life on the Earth. More than 70% of the human body is made of water, in childhood age is more than 80% and when you get old it will change to less than 60%. The water content of the organs in our body high too, roughly 86% of the blood, 84% of the liver, 78% of the brain, 77% of the heart and 70% of the muscels. If you lost your 50% water quantity of your body you may die. If 2 or more than 3 days  you don't drink water you will die too. It is very important to drink 2-3 liters of water.