An organism that regulates its body temperature using external heat sources is an example of

Answer : Ectotherm (cold-blooded animal).

Explanation : An organism that regulates its body temperature using external heat sources is an example of an Ectotherm.

Any cold-blooded animal can be called as an Ectotherm; They are any animal which requires regulation of body temperature according to their environnment and depend on external sources, such as sunlight or a heated rock surface.

These ectotherm includes the category of fishes, amphibians, reptiles, and invertebrates in their class.

A cold-blooded animal. Cold-blooded animals can't generate heat themselves so they have to use external sources to keep them warm.