In a hydra, digestion is completed in a hydra, digestion is completed in the alimentary canal in the gastrovascular cavity intracellularly extracellularly

intracellularly

Explanation:

Green Hydra Scientific name hydra viridissima, is one of the simplest animals among multicellular Celentéreos animals. It belongs to the Hydrozoans.

The green hydra has a simple cavity that communicates to the outside through the mouth, which is surrounded by tentacles. Nutrition is effected by the pressure of small animals such as tiny Crustaceans, larvae of Insects, among others, sometimes swallowing prey larger than itself. By touching the animal with its tentacles to an animal all the nematocysts are discharged at the same time, some inoculate the paralyzing substance they possess; while others are rolled over the victim's body. Once this happens the tentacles are responsible for driving the food into the mouth, where it enters the gastrovascular cavity. The food undergoes in that cavity an extracellular digestion motivated by the gastric juices segregated by the glandular cells that cover this cavity, in something similar to the digestion that takes place in the superior animals. Flagellated cells move nutrient fluid that is in the gastric cavity and seize the undissolved particles, which are encompassed by those cells and directed inside. This intracellular digestion is analogous to that performed by the Protozoa. Insoluble particles are expelled through the mouth's own opening.