Answer:
in human body, the diffusion of different chemicals and gases is important functions in the body. useful molecules enter and waster products are removed from body during diffusion. oxygen and carbon dioxide are diffused in the lungs .
Diffusion of water, salts and waste products occur in the kidneys. The waste products also evaporates in the form of sweating. The diffusion does not require much energy which is advantage of it.
calcium is diffused in to the cells from the food across the intestinal mucosa. when there is need of calcium, it get released from the bones and small intestine will then start absorbing calcium.
Studies have shown that the movement of calcium into intestinal cells is both passive diffusion.