The respiratory systems of fish and birds are similar in that both______________.
A)utilize air sacs.
B)have similar partial pressures of oxygen in the environmental medium.
C)have unidirectional flow of the environmental medium over the gas exchange surfaces.
D)employ countercurrent exchange.

Question

Quizplus · Accepted Answer

Both fish and birds have a unidirectional flow of the environmental medium over their gas exchange surfaces, which allows for efficient oxygen uptake.

The Respiratory Systems of Fish and Birds Are Similar in That