Concept:Lungfish have lungs that work as accessory respiratory organs to assist gill respiration while living in water.
Explanation:Lungfish are aquatic fish that possess both gills and lungs.
Their gills alone may not extract enough oxygen from water, especially in stagnant or poorly oxygenated conditions.
Therefore, the lungs enable them to breathe atmospheric air while in water, thereby complementing the gills.
This adaptation also helps them survive dry periods, but its main function is to support gill respiration in an aquatic environment.
Lungs do not function mainly to replace gills on land, since gills cannot operate outside water.
Thus, the lungs are an adaptation for respiration that supplements the gills while the fish is still in water.
Answer:A. to complement gills while in water