Final answer:
The transformation of aquatic animals with gills into terrestrial animals with lungs is called metamorphosis. Amphibians, for example, undergo metamorphosis from tadpole stage, losing their gills and developing lungs and limbs that equip them for life on land.
Step-by-step explanation:
The process of transforming from an aquatic animal with gills into a terrestrial animal with lungs is called metamorphosis During the transition from water to land, aquatic animals like amphibians undergo significant changes. This is known as metamorphosis, a biological process where an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure.
An example of this is seen in frogs that start as tadpoles with gills and tails suited for an aquatic environment. As they undergo metamorphosis, they lose their gills and tail, develop lungs for breathing air, and grow limbs for mobility on land. Other necessary adaptations include changes to the skin that must remain moist to allow for gas exchange. The transition results in the ability to inhabit terrestrial environments as adult amphibians.