Why Is the Respiratory System of a Bird More Efficient

Multiple Choice

Why is the respiratory system of a bird more efficient than the human respiratory system?

A) The bird respiratory system does not mix exhaled air with inhaled air.
B) A bird lung contains multiple alveoli, which increases the amount of surface area available for gas exchange.
C) The human respiratory system ends in small parabronchi, which reduce the amount of surface area available for gas exchange.
D) Only B and C are correct.
E) A, B, and C are correct.