Which part of the respiratory system is the primary site of gas exchange?
A
Alveoli
B
Trachea
C
Bronchi
D
Larynx
Correct Answer: Option A — Alveoli
Explanation:
Alveoli are tiny, thin-walled air sacs in the lungs where oxygen from inhaled air diffuses into the blood while carbon dioxide diffuses out. Their vast surface area and thin walls maximize efficient gas exchange.