Nokea
The movement of both oxygen and carbon dioxide in the body is accomplished by
Correct Answer: D
Rationale: The correct answer is D: diffusion. Oxygen and carbon dioxide move in and out of cells through simple diffusion, which is the passive movement of molecules from an area of high concentration to an area of low concentration. This process occurs due to the concentration gradient of these gases. Osmosis (Choice C) is the movement of water across a selectively permeable membrane, not gases like oxygen and carbon dioxide. Exocytosis and endocytosis (Choice A) involve the transport of larger molecules and particles in and out of cells, not gases. Bulk flow (Choice B) involves the movement of fluids in response to pressure differences, not the specific movement of oxygen and carbon dioxide molecules. Therefore, diffusion is the correct mechanism for the movement of oxygen and carbon dioxide in the body due to their small molecular size and the concentration gradient present.