What is the Respiratory Surface Where Gas Exchange Occurs

Question

What is the respiratory surface where gas exchange occurs?
A) trachea
B) bronchioles
C) pharynx
D) alveoli

Accepted Answer

Gas exchange occurs at the alveoli, which are small sacs in the lungs where oxygen and carbon dioxide are exchanged between the air in the lungs and the blood in nearby capillaries. The trachea, bronchioles, and pharynx are all part of the respiratory system, but gas exchange does not occur in these structures.