Animals are heterotrophic, which implies they depend on other organisms—crops and/or other animals—for their meals, as they cannot synthesize their unique food as crops do by using photosynthesis. The fossil document of animals goes again about 600 million a long time to the Ediacaran period of time, or somewhat previously. https://paxtonybhrn.therainblog.com/35169203/5-simple-statements-about-animal-xxx-explained