A vertebrate that begins its life breathing water and grows up to breathe air as an adult is an?

A vertebrate that begins its life breathing water and grows up to breathe air as an adult is an amphibian. Amphibians, such as frogs and salamanders, typically start their life cycle as aquatic larvae with gills for breathing underwater. As they mature, they undergo metamorphosis, developing lungs to breathe air as adults. This dual life cycle is a defining characteristic of amphibians.