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

Multiple Choice

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