You prop open the gill covers of a fish, tie a string around its tail, and tow it backward through the water. This action forces water to flow in the back of the gill covers, from back to front over the gills, and out through the fish's mouth. What effect would this backward movement have on gas exchange?
A) The only effect would be the fish's discomfort from this treatment.
B) It would increase efficiency of gas exchange.
C) It would reduce efficiency of gas exchange.

Question

Quizplus · Accepted Answer

Towing a fish backward disrupts the normal flow of water over the gills, which is crucial for efficient gas exchange. Normally, water enters through the mouth and flows over the gills in a front-to-back direction, allowing for optimal oxygen uptake and carbon dioxide release. Reversing this flow disrupts the counter-current exchange mechanism, reducing the efficiency of gas exchange.

You Prop Open the Gill Covers of a Fish, Tie