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.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.