Ineed some • define diffusion as the movement of atoms and molecules from an area of higher concentration to an area of lower concentration, and explain its importance.

Let me take an example: Diffusion appear in a process in our body called Gas exchange between the lungs and blood vessels. Here is how it works:

- First of all, the alveolus in your body are located near your blood vessels. Oxygen in your aviolus will move into the blood vessels to be transfered into your cells, and carbon dioxide will move the opposite way until the amount of each kind of gas in every place is equal. At this moment, there will be more oxygen in your blood vessels (specifically red blood cells) and more carbon dioxide in your aviolus.

=> That is just one of many examples for us to see that diffusion is so important and is pretty much the method how substances move in and out of cells in your body.

"a.) well–developed vascular system."