Fish in a marine environment must maintain a relatively constant ion concentration in their tissues and blood. How do the chloride cells in the gills aid fish in the removal of excess ions? A. the chloride cells create a countercurrent system where water is lost from the body and chloride ions are absorbedB. the chloride cells create a countercurrent system where ions are lost from the body and water is absorbed to dilute other ions (NaCl) C. the chloride cells actively move ions into the body and water follows by osmosisD. the chloride cells actively remove ions from the body and water follows by osmosis

D. The chloride cells actively remove ions from the body and water follows by osmosis

Explanation:

Marine fishes have hypotonic interior compared to the surrounding water and tend to lose water osmotically. These fishes in marine water drink lots of water and use both gills and kidneys to maintain the constant ion concentration in tissues and blood.

These fishes have special cells called "chloride cells" in the gills. These cells serve in the active transport of chloride ions and the passive transport of sodium ions.

The loss of these ions from the body results in an osmotic gradient that drives the osmotic movement of water.