All animals must obtain what from outside sources?

we r all homosapians.not homosexuals,homosapians. we eat food and our bodies obsorbe the nutrience. .

This is because of classification. It's the way scientists identify living things, and the term "animal" is one of the broader terms. So it all narrows down from "Plant" and "Animal", into different...

Well they eat and avoid predators.Eat or be eaten.Sorry the answer is so simple, just they DO need to eat.

Konichiwa

yes