''Water''
Your body is mainly made
of water more than sixty percent.
You can survive weeks without food
but no more than a few days without water.
You gain water by drinking and eating and
as a by product of cell activity.
You lose water by sweating and
breathing and in your urine and feces.
The water balance in the body is controlled
mainly by the kidneys and adtenal glands.
In addition, if you drink a lot of water the saltiness of
the blood is diluted watered down. To restore the balance
the kidneys let out a lot of water as urine.