Heterotrophs are sectioned off into three different categories based on their intake of food. Heterotrophs are organisms that use organic compounds for energy and carbon. Herbivores, being animals that eat plants are; algae-eating snails, sapsucking insects, and vertebrates such as cows, horses, rabbits, and sparrows. Carnivores, animals who eat other animals; crabs, squid, many insects, cats, eagles, trout, and frogs. Omnivores, animals who eat both plants and other animals are; humans, pigs, bears, and crows. Depending on what their diet and structure is, animals will have a different digestive system. Invertebrate’s digestive system are bags or tubes. For example, flatworms such as planarians, contain only one opening that serves for both
