one
A gastrovascular cavity is a digestive sac with only a single opening. A complete digestive tract (otherwise known as an Alimentary canal) has two openings (a mouth and anus) between its digestive tubes unlike the gastrovascular cavity in which food is ingested and eliminated through the same opening (example would be hydra)
A digestive sac not related to other endomembrane structures
lysosomes
The stomach
has only a single openning
The stomach
Jellyfish have a body type that is like a sac. They eat with their large stomach sacs, which are called coelenterons.
A lysosome is a sac of digestive enzymes, used to break down monosaccharaides and disaccharides. Lysosomes are found in animal cells and are also called suicide sacs.
A sac body plan is a simple body organization found in some animals, where the body consists of a central cavity surrounded by a single layer of cells. This cavity acts as a digestive chamber where food is taken in and digested. Examples of animals with a sac body plan include cnidarians like jellyfish and sea anemones.
A complete digestive tract, also known as a tube-within-a-tube system, features a separate mouth and anus, allowing for a more efficient and continuous flow of food and waste. In contrast, a sac-like digestive tract, found in organisms like jellyfish, has only one opening that serves as both mouth and anus, leading to a less efficient digestion process where food and waste can mix. This structural difference impacts nutrient absorption and the overall efficiency of digestion.
Lysosomes
Peroxisomes.