What is the primary site of gaseous exchange in human lungs?

💡 Solution & Explanation

Alveoli are microscopic, thin-walled air sacs situated at the terminal ends of the respiratory bronchioles where active gas exchange occurs between inspired air and pulmonary capillaries. Conduction airways like the trachea and bronchi only transport air without participating directly in diffusion. The vast surface area of human alveoli facilitates rapid diffusion of oxygen into the bloodstream.