A cell is in a solution that contains dissolved oxygen as the cell used oxygen for respiration

oxygen in the solution will naturally diffuse into the cell.

Explanation:

Cells require oxygen for cellular respiration to occur. When a cell is places in a solution having oxygen dissolved in it, The concentration of the oxygen outside the cell will be more as compared to the concentration of oxygen inside the cell. As a result, the cell will take up oxygen by the process of diffusion. Diffusion is the movement of particles from a higher concentration to a lower concentration along a concentration gradient.