The term for animals that live in both aquatic and terrestrial environments is "amphibians." Amphibians are a class of vertebrates that generally undergo metamorphosis from a juvenile aquatic form to an adult terrestrial form. Common examples include frogs, toads, salamanders, and newts. Amphibians typically have moist skin that allows for respiration through their skin, in addition to lungs in their adult forms. This dual lifestyle makes them highly sensitive to environmental changes, as they require both water and land ecosystems to thrive. As a result, amphibians are often considered indicators of environmental health due to their sensitivity to pollution and habitat loss.