Answer:
Simple diffusion
Explanation:
Carbon dioxide is a small, uncharged molecule that can easily pass the lipid bilayer of the cell membrane. Other similar molecules include oxygen and water. Carbon dioxide passes the cell membrane via simple diffusion. Water crosses the cell membrane by osmosis.
You can also tell this from the image because the carbon dioxide is moving from a high concentration to a low concentration without the aid of any proteins as in active transport (a carrier pump) or facilitated diffusion (a protein with a pore)
