Why is gas exchange more difficult for aquatic animals with gills than for terrestrial animals with lungs?
A)Water is less dense than air.
B)Water contains much less O2 than air per unit volume.
C)Gills have less surface area than lungs.
D)Gills allow only unidirectional transport
E)Gills allow water to flow in one direction

Question

Quizplus · Accepted Answer

Water contains much less O2 than air per unit volume, meaning that aquatic animals must extract oxygen more efficiently from the water through their gills. This requires a larger surface area and greater energy expenditure compared to terrestrial animals with lungs, making gas exchange more difficult for aquatic animals with gills.

Why Is Gas Exchange More Difficult for Aquatic Animals with Gills