What would be the consequence if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, then out the mouth? This reversal of water flow would ________.
A) reduce efficiency of gas exchange
B) change the exchange of gases in the body from carbon dioxide out and oxygen in to carbon dioxide in and oxygen out
C) increase the efficiency of gas exchange

Question

Quizplus · Accepted Answer

Reversing the direction of water flow over the gills would reduce the efficiency of gas exchange because it would not allow for the efficient removal of carbon dioxide and uptake of oxygen. The normal flow of water over the gills allows for a concentration gradient to be created in which oxygen can diffuse from the water into the blood of the fish while carbon dioxide can diffuse out. Reversing the direction of water flow would disrupt this gradient and decrease the efficiency of gas exchange. Choice B is incorrect because the direction of gas exchange would remain the same. Choice C is incorrect because the efficiency of gas exchange would actually decrease.

What Would Be the Consequence If We Were to Reverse