Explanation:
The diffusion phenomenon is generated by the difference of concentration of a gas between two reference points.
In this case, the two points are: the inside of the cell and the surroundings of it.
The diffusion of oxygen will depend then of the concentration of it in the cell and the concentration in the outside:
[tex]\Delta O_2= Oxygen_{outside} - Oxygen_{cell}[/tex]
The bigger this difference, the higher the diffusion rate of oxygen entering the cell.