Describe two examples of diffusion as it occurs in living organisms.Diffusion in living organisms.

Diffusion or passive transport occurs in living organisms
without any additional input of energy. The process simply occurs if the concentration
gradient is such that there is a concentration difference of a particular substance
outside and inside a cell membrane. The substance must have small enough molecules to
fit through the pores in the membrane.  For example, if there is a higher concentration
of glucose in the bloodstream,relative to the level inside the body cells, glucose
passes through the capillary walls and will diffuse into the cells, from high to low
concentration.  Another example would be osmosis, a special type of diffusion that
occurs when the substance water passes through a cell membrane. If a cell is surrounded
outside, by a high concentration of water relative to the inside of the cell,  as when
you water a plant, the water passes into the cell from high concentration outside, to
low concentration inside. Eventually, when an equilibrium is established on either side
of the membrane, diffusion will stop.