You Prop Open the Gill Covers of a Fish, Tie

Multiple Choice

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.