Answer:
The correct answer is option - passive diffusion
Step-by-step explanation:
Diffusion is the movement of the substance molecules from a high concentration to low concentration region. It can be through carrier proteins or protein channels or without any help. The movement through the channels or carriers is termed as facilitated diffusion and diffusion without any help is known as passive diffusion.
The movement of the carbon dioxide and oxygen move through the passive diffusion as oxygen is non polar it does not need anything to move. Carbon dioxide is polar molecule but very small in size so they also move through passive diffusion.
Thus, the correct answer is option - passive diffusion.