Answer: amphibians

AnswerCrossword Clue
amphibiansA seaplane, tank, or other vehicle that can operate on land and on water
amphibiansAMPHIBIAN, any cold-blooded vertebrate of the class Amphibia, typically living on land but breeding in water, that includes newts and salamanders, frogs and toads, and caecilians
amphibiansA cold-blooded vertebrate animal of a class that comprises the frogs, toads, newts, and salamanders. They are distinguished by having an aquatic gill-breathing larval stage followed (typically) by a terrestrial lung-breathing adult stage