Animals are heterotrophic, meaning they rely upon other organisms—crops and/or other animals—for his or her food, as they can not synthesize their own personal food stuff as crops do by using photosynthesis. The fossil report of animals goes again about 600 million yrs on the Ediacaran period, or fairly before. https://animalsex15047.wikiitemization.com/5174067/animal_sex_fundamentals_explained