Here's a breakdown:

* Diffusion: The movement of molecules from an area of high concentration to an area of low concentration. This happens naturally due to the random motion of molecules and their tendency to spread out and occupy available space.

* Concentration: The amount of a substance present in a given volume.

Diffusion is a fundamental process in many biological and chemical systems, playing a role in:

* Gas exchange in the lungs: Oxygen diffuses from the air into the blood, and carbon dioxide diffuses from the blood into the air.

* Nutrient transport in the body: Nutrients diffuse from the small intestine into the bloodstream.

* Waste removal: Waste products diffuse from cells into the bloodstream.

* Perfume spreading in a room: Perfume molecules diffuse from the source into the air.

Let me know if you'd like more details on diffusion!