The circulatory systems of bony fishes, rays, and sharks are most similar to ________.
A) those of birds, with a four-chambered heart
B) the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber
C) those of sponges, where gas exchange in all cells occurs directly with the external environment
D) those of humans, where there are four pumping chambers to drive blood flow

Question

Quizplus · Accepted Answer

The circulatory systems of bony fishes, rays, and sharks have a portal system similar to that found in mammals, where blood passes through two capillary beds in sequence without passage through a pumping chamber. This is in contrast to humans, birds, and other vertebrates, which have a four-chambered heart to pump blood through the circulatory system. Sponges, on the other hand, do not have a circulatory system or specialized gas exchange structures, so they are not a good option to compare with these fish.

The Circulatory Systems of Bony Fishes, Rays, and Sharks Are