Correct Answer:
Option A - Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. They inhabit a wide variety of habitats with most species living within terrestrial, fossorial, arboreal or fresh water aquatic ecosystem, amphibians start out as larvae living in water. The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians have a 3-chambered heart with two atria and a single ventricle.
A. Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. They inhabit a wide variety of habitats with most species living within terrestrial, fossorial, arboreal or fresh water aquatic ecosystem, amphibians start out as larvae living in water. The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians have a 3-chambered heart with two atria and a single ventricle.