Water in living things
Most of the body weight of a living thing is water. It is not an organic compound but an inorganic one.
How much?
About two thirds of the body weight of most living things is water. More than half of what you weigh is water.
Where life began
Life on earth originated in water. Water is an essential medium for the existence of living matter.
Properties of a simple water molecule
The composition of water is very simple — two hydrogen atoms and one oxygen atom. Yet that simple molecule shows a set of unusually useful properties.
It is an excellent solvent
It acts as a transport medium
It acts as a respiratory medium
Its specific heat capacity is high
Ice is less dense than water