Diffusion is important to cells because it allows them to gain the useful substances they require to obtain energy and grow, and lets them get rid of waste products.

Why is diffusion important in science?

Diffusion occurs in liquids and gases when their particles collide randomly and spread out. Diffusion is an important process for living things - it is how substances move in and out of cells.

Why is diffusion so important to humans?

Diffusion is very important in the body for the movement of substances eg the movement of oxygen from the air into the blood and carbon dioxide out of the blood into the air in the lungs, or the movement of glucose from the blood to the cells.