WATER

Water is a colourless,transparent liquid destitute of taste and smell,possessing a natural reaction,a compound of two portions by weight of hydrogen with one of oxygen.
You can live for many days without food,but you would die after a few days without water.If your body was dried out completely,it would weight less than half of its present weigh.Water is an essential part of the body cells and blood and is used to carry waste and poisons out of the blood in the urine.
The skin is water proof and keep body water in,but you lose water all the time in the breath,the sweat and the course in the urine

Regulating the water in the body
The kidneys take water from the blood and pass it into the bladder as urine.If the body is short of water ,than less water is used in the urine and it is darker in colour.If the body is has more water than it needs,a lot of weak in the body.This kind of regulating, when the body adjusts to keep everything at a certain level, is called HOMEOSTASIS.

Sweating
Sweating is part another regulating system.The body works best at certain level of heat or temperature which is kept constant.When you run about,the movement of the muscules  produces heat and this may raise the temperature of the body.To stop this happening,sweat is produced on the surface of the skin,which cools the body as it dries.
Sweating also helps you to keep cool on hot day.You may also sweat for emotional reason(such as fear or embarrasment) even if you cold

Replace the Water
As well as losing water in the urine and the sweat, some is lost each time you breath out.
A person needs to take in up to1.65 liters of water everyday to replace what has come out of the body. Not  all this needs to be in the form of drinks, because many foods also contain water.