Diffusion occurs because of the movement of molecules from
the region of higher concentration to the region of lower concentration. This
movement of molecules occurs due to a thermal motion. Diffusion normally occurs
between two compartments having difference in concentration. In case of fluid
it moves from the region of higher concentration to the region of concentration
until a balance is reached. The process of diffusion is very important for the
humans as well. The oxygen that humans breathe in gets diffused with the blood.
