In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant. 
Q: Air is brought in through the mouth. Passes through the lungs. And into the bronchial tissue. The carbon dioxide is removed. The lungs bring the oxygen to the rest of the body. 
A: 
air ,carbon dioxide ,oxygen 