alot of people don't know!
An opening
A digestive chamber with one opening is called a gastrovascular cavity. This structure is typically found in simple organisms such as cnidarians and flatworms, where it serves both digestive and circulatory functions.
a digestive system with a single opening
Cnidarians.
Cnidarians accomplish digestion using a gastrovascular cavity, which serves both digestive and circulatory functions. Food is taken in through a single opening, where it is digested extracellularly, and the nutrients are then absorbed by the surrounding cells. This simple body plan allows cnidarians, such as jellyfish and sea anemones, to efficiently process their food without a complex digestive system.
Most cnidarians have tentacles with stinging cells surrounding their mouth. The mouth is the only body opening. All cnidarianshave radial symmetry.
A) Only one opening: they expel undigested material through the mouth.
Digestion and absorption of food are major functions of gastrodermis .
Just one, the mouth and anus in one. Food goes in and is taken up by the body, and waste comes out.
Mainly through suspension feeding. Cnidarians use stinging tentacles (nomocytes) to capture their prey. Once the tentacles grab the food it is absorbed in the gastrovascular cavity (stomach) and taken in asnutrients.
Jellyfish simply shoot out anything that can't be digested via their single,multi-use opening since they are Cnidarians
True, tentacles are a common feature among cnidarians like jellyfish and sea anemones. These structures are typically armed with stinging cells called cnidocytes, which help cnidarians capture prey and defend against predators. Tentacles are used for a variety of functions including feeding, sensing the environment, and locomotion.