collection of waste material breakdown of materials diffusion of material storage of materials
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Capillary walls are only one layer of cells thick. Passage of oxygen into and out of the capillaries is controlled most by which process?
Possibilities:
- collection of waste material
- breakdown of materials
- diffusion of material
- storage of materials

diffusion of material