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. 
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Question: You breathe in. Air goes through all the little branches in your lungs to fill up the air sacs, or alveoli. Oxygen goes through the walls of the alveoli and into the capillaries. The oxygen goes into the bloodstream. Oxygen is left and carbon dioxide is picked up. You breathe it out through your lungs. 

Answer: air ,oxygen ,carbon dioxide 


Question: Chemical reactions break down the bonds holding the rocks together. The rocks fall apart. They form smaller and smaller pieces. Oxidation takes place when oxygen combines with other elements in rocks. They form new types of rocks. The new substance is softer. Carbonation takes place when carbon dioxide reactions with certain types of rocks. A solution is formed that can easily be carried away by water. 

Answer: rocks ; smaller pieces ,oxygen ,new types of rocks ; new substance ; certain types of rocks 


Question: The salt water is heated. As the saltwater is heated the water becomes a gas. The salt particles sink to the bottom of the container. Gaseous water is piped into another container. Allowed to cool. The salt particles are left behind in the first container. The second container contains fresh water. 

Answer:
salt water ,gas ,gaseous water ,salt particles ,fresh water