Q.:- How do substances like CO2 and water move in and out of the cell? Discuss.
Substances like CO2 (a cellular waste) accumulates in high concentration 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.