Which of the following is/are the cellular waste(s) that needs to be excreted out by the cell through the process of diffusion? a. CO₂ b. O₂ c. H₂O

CO₂ is the cellular waste that needs to be excreted out by the cell. It accumulates in high concentrations inside the cell. In the cell’s external environment, the concentration of CO₂ is low as compared to that inside the cell. As soon as there is a difference of concentration of CO₂ inside and outside a cell, CO₂ moves out of the cell, from a region of high concentration to a region of low concentration outside the cell by the process of diffusion. Thus, this is the correct answer.