Question

because of diffusion, unwanted ______ is able to diffuse out of cells. oxygen (o2) carbon dioxide (co2)

Explanation:

Cells produce carbon - dioxide as a waste product during cellular respiration. Through diffusion, substances move from an area of higher concentration to an area of lower concentration. Since carbon - dioxide is a waste product with a higher concentration inside the cell compared to the outside in the bloodstream or surrounding environment, it diffuses out of the cells. Oxygen, on the other hand, diffuses into the cells for cellular respiration.

Answer:

Carbon dioxide (CO2)