Which anatomical structure in human lungs provides the vast, thin surface area necessary for rapid gas exchange with blood capillaries?
Answer and explanation
Correct answer: A. Alveoli
- Step 1: Gas exchange requires a massive surface area and minimal diffusion distance. Step 2. The millions of microscopic air sacs known as alveoli provide roughly 70 to 100 square metres of respiratory surface. Answer: Alveoli. Why not the others: Trachea and bronchioles are conducting airways; pleural cavity is the fluid-filled space surrounding the lungs.
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