Three percent is freshwater found in glaciers and ice, below the ground, or in rivers and lakes.
Fatty acids are important for the cell membrane because the fatty acids present in membrane is cholesterol which provides the fluidity and mechanical support to the cell membrane.
Nonpolar and small polar moleculescan pass through the cell membrane, so they diffuse across it in response to concentration gradients. Carbon dioxide and oxygen are two molecules that undergo this simple diffusion through the membrane. The simple diffusion of water is known as osmosis.
