How do substances like carbon dioxide (C{O_2}) and water ({H_2}O) move in and out of the cell? A) Diffusion and osmosis B) Reverse osmosis and diffusion C) Facilitated diffusion and diffusion D) None of these

The movement of substances like carbon dioxide (CO2) and water (H2O) in and out of the cell primarily occurs through various mechanisms, including diffusion and facilitated diffusion.

Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration, driven by the concentration gradient. Both carbon dioxide and water can move across the cell membrane through simple diffusion, as they can pass directly through the lipid bilayer due to their small size and non-polarity.

Facilitated diffusion, on the other hand, involves the movement of molecules across the cell membrane with the help of specific transport proteins. While carbon dioxide can diffuse directly through the lipid bilayer, some cells may use facilitated diffusion for water movement through aquaporin proteins, which act as channels for water molecules.

So, the correct answer is:

C) Facilitated diffusion and diffusion