Which of the following is an example of countercurrent exchange?
A)the flow of water across the gills of a fish and that of blood within those gills
B)the flow of blood in the dorsal vessel of an insect and that of air within its tracheae
C)the flow of air within the primary bronchi of a human and that of blood within the pulmonary veins
D)the flow of water across the skin of a frog and that of blood within the ventricle of its heart
E)the flow of fluid out of the arterial end of a capillary and that of fluid back into the venous end of the same capillary

Question

Quizplus · Accepted Answer

Countercurrent exchange involves the opposite movement of two different fluids in close proximity, allowing for efficient transfer of substances between them. The flow of water across the gills of a fish and that of blood within those gills is a classic example of countercurrent exchange, as the water flows in one direction while the blood flows in the opposite direction, maximizing oxygen exchange. The other choices do not involve true countercurrent exchange.

Which of the Following Is an Example of Countercurrent Exchange