Here's a short story:

Ctenophora (/tᵻˈnɒfərə/; singular ctenophore, /ˈtɛnəfɔːr/ or /ˈtiːnəfɔːr/; from the Greek κτείς kteis 'comb' and φέρω pherō 'carry'; commonly known as comb jellies) is a phylum of animals that live in marine waters worldwide. Their most distinctive feature is the ‘combs’ – groups of cilia which they use for swimming – they are the largest animals that swim by means of cilia. Adults of various species range from a few millimeters to 1.5 m (4 ft 11 in) in size. Like cnidarians, their bodies consist of a mass of jelly, with one layer of cells on the outside and another lining the internal cavity. In ctenophores, these layers are two cells deep, while those in cnidarians are only one cell deep. Some authors combined ctenophores and cnidarians in one phylum, Coelenterata, as both groups rely on water flow through the body cavity for both digestion and respiration. Increasing awareness of the differences persuaded more recent authors to classify them as separate phyla. (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: What is this article about?
Guess: Ctenophora

Question: Where is this word derived from?
Guess: the Greek κτείς kteis 'comb' and φέρω pherō 'carry

Question: What are they known as?
Guess: comb jellies

Question: What makes them unique?
Guess: the comb like cilia

Question: How do they move? By using what?
Guess: They move using Cilia

Question: Are there any similar creatures?
Guess: yes

Question: What are they called?
Guess: Cnidarians

Question: What are they made of?
Guess: consist of a mass of jelly

Now answer the following question in the same format.

Question: What do they use for breathing?

water flow