Animals can have two kinds of digestive system. There is a dead-end digestive system and a one-way digestive system. Death digestive system is a digestive system in which animals eat food, then digest it and digest it through animals. Animals such as sponges and echinoderms have this digestive system. On the other hand, the one-way digestive system is a food source that digests food and food, not the other end of the animal. Animals such as antelope, mollusk, chordate (vertebrate), arthropod and other animals have this digestive system.
Sponge has a dead end digestion system. This means that what they eat and digestion come from the same place. There is also a dead end digestive system which is a cnidid animal. However, Annelids has a different digestive system from the one - way digestive system. This means the mouth is away from the anus. Mollusks also have a unidirectional digestive system like arthropods. The ganglion is radially symmetric. This means they are periodic. Although the sponge is not radially symmetrical, it is asymmetrical. Asymmetry means that classes are essentially asymmetric. Mollusks are none of them, but they are symmetrical. Symmetry means that the left part of the dog is the same as the right part of the dog, and then it becomes symmetrical. Bilateral symmetry is also an arthropod