LIFE SCIENCE

Detailed explanation-1: -ectotherm, any so-called cold-blooded animal-that is, any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface. The ectotherms include the fishes, amphibians, reptiles, and invertebrates.

Detailed explanation-2: -Endotherms, such as birds and mammals, use metabolic heat to maintain a stable internal temperature, often one different from the environment. Ectotherms, like lizards and snakes, do not use metabolic heat to maintain their body temperature but take on the temperature of the environment.

Detailed explanation-3: -Reptiles and amphibians are ectotherms, while birds are endotherms. An ectotherm (reptile/amphibian) relies primarily on its external environment to regulate the temperature of its body. Endotherms (birds) are able to regulate their body temperatures by producing heat within the body.