Animals are heterotrophic, which means they count on other organisms—vegetation and/or other animals—for their meals, as they can't synthesize their unique food items as crops do by using photosynthesis. Vertebrates make up a self-contained team: the subphylum Vertebrata. Invertebrates belong to a variety of groups. A crustacean’s system is shielded https://connerezskc.mysticwiki.com/1625524/animal_sex_fundamentals_explained