To which group of animals do frogs belong?

Frogs belong to the group known as amphibians, which is characterized by their life cycle that typically includes both aquatic and terrestrial stages. Amphibians, such as frogs, toads, and salamanders, are notable for their ability to live both in water and on land, and they usually undergo a metamorphosis from a larval stage (like tadpoles in the case of frogs) to their adult form.

The defining features of amphibians include their smooth, permeable skin that allows for gas exchange, their structure that enables them to live in various environments, and their reproductive strategies often involving eggs laid in water. This makes them distinct from reptiles, mammals, and fish. For instance, reptiles are primarily adapted to land life and have dry skin, while mammals give birth to live young and have hair or fur. Fish, on the other hand, are primarily aquatic and breathe through gills. Thus, the classification of frogs as amphibians is based on their unique biological and ecological characteristics, setting them apart from the other groups mentioned.