Answer the following question given this paragraph: 

Cnidarians have an incomplete digestive system with a single opening. The opening is surrounded by tentacles, which are covered with nematocyst cells and used to capture prey. Digestion takes place in the digestive cavity. Nutrients are absorbed and gases are exchanged through the cells lining this cavity. Fluid in the cavity supports and stiffens the cnidarian body.


Q: What organism is characterized by an incomplete digestive system and a single, tentacled opening?

 Choices:

- annelids

- prokaryotes

- sponges

- cnidarians

A:
cnidarians
