I need help plz asap

when an animal has a simple structure of only one cell, they get their nutrients from their environment. when animals have a more complex structure, you and infer that they are multicellular and they have a specialized way of breaking down their food. thus, meaning they can be herbivores, omnivores, or carnivores.
You can look at their anatomical structures to see what structures they use to digest said food. For instance, if you were to look at a skeleton and saw that the animal had strong, flat-topped teeth, one would assume they are plants because those strong molars are needed to chew the tissue of plants.