Why is diffusion insufficient to meet the oxygen requirements of multi - cellular organisms like humans?
- Diffusion is the movement of a substance from an area of higher concentration to an area of lower concentration.
- Diffusion occurs in multicellular organisms too, although it takes place on a cellular level .
- Diffusion is a slow process. So, it will take a longer time over a much larger distance for oxygen to reach every cell of the body.
- The volume of the human body is so large that oxygen cannot diffuse into all the cells in time to keep up with our metabolic needs.
- Hence, diffusion is insufficient to meet the oxygen requirements of large multicellular organisms.