Which term refers to the exchange of oxygen and carbon dioxide in respiration?

• A. Gas Exchange
• B. Echolocation
• C. Endotherm
• D. Exoskeleton

Answer: (A)

Gas exchange is the process by which oxygen enters the body and carbon dioxide is released during respiration. It happens by diffusion across a respiratory surface, driven by differences in partial pressures: oxygen moves from the air-filled spaces of the lungs into the blood, and carbon dioxide moves from the blood into the lungs to be exhaled. The thin, moist surfaces of alveoli and the surrounding capillaries maximize this diffusion, enabling efficient gas transfer for cellular respiration. The other terms refer to different ideas—echolocation is using sound to locate objects, endotherm describes maintaining body temperature metabolically, and exoskeleton is an external skeleton. So gas exchange is the term for this gas transfer during respiration.