Across Which Structure(s)does Most Gas Exchange Occur

Question

Across which structure(s)does most gas exchange occur?
A) Trachea
B) Bronchus
C) Bronchioles
D) Alveoli

Accepted Answer

Gas exchange primarily occurs in the alveoli, where oxygen diffuses into the bloodstream and carbon dioxide diffuses out. The trachea, bronchus, and bronchioles primarily serve as passageways for air to reach the alveoli.