Answer: The assertion is true and the reason is the correct explanation of the assertion
Explanation: This statement is true because the plasma membrane is selectively permeable, meaning that it allows some substances to pass through it while preventing others from crossing it. Gases like oxygen and carbon dioxide are small molecules that can easily diffuse through the membrane due to their size and lack of charge. Additionally, the plasma membrane has channels and pumps that specifically facilitate the movement of gases across the membrane. Therefore, metabolic gases can freely diffuse across the plasma membrane due to the permeability of the membrane.