A frog is an amphibian, belonging to the order Anura. Amphibians are characterized by their life cycle, which typically includes an aquatic larval stage followed by a terrestrial adult stage. Frogs are known for their smooth, moist skin and strong hind legs, which they use for jumping and swimming. They possess unique adaptations, such as permeable skin, allowing for gas exchange and hydration. Frogs inhabit diverse ecosystems, from rainforests to deserts, and play essential roles in their environments as both predators and prey. They are also indicators of ecosystem health due to their sensitivity to environmental changes.