Darters are fish that live in fast-running rapids;they eat surface insects,they rest on the bottom avoiding the push of the water,and make brief frantic dashes to the surface to feed.If they swam midstream,they would expend a huge amount of energy.What physiological strategy allows them to live on the bottom?
A)Lack of gills
B)Loss of a lateral-line
C)Loss of a swim bladder
D)Reduction in fin size and number
E)Expansion of a swim bladder into a lung

Question

Quizplus · Accepted Answer

Darters have reduced swim bladders or completely lack them, which reduces their buoyancy and allows them to stay on the bottom without expending too much energy.

Darters Are Fish That Live in Fast-Running Rapids;they Eat Surface