Why does diffusion need to occur?

Question

Why does diffusion need to occur? Is there a reason?

Answer 1

Diffusion needs to occur
1. To allow oxygen into out blood from the alveoli in the lungs to the capillaries surrounding the alveoli and to get oxygen into every cell in our body.
2. To allow CO2 to escape our body, to diffuse from cells into the blood and from the the blood into the alveoli to be breathed out.
3. To absorb nutrients from the small intestine into our blood and into our cells.

Answer 2

to maintain equilibrium in the system. things move from an area of higher concentration to lower concentration. thus, when you have a system in which a concentration of something is lower than it needs to be, diffusion allows that thing to move into the system thereby maintaing equilibrium.