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. 

Ex Input:
Chemicals like sulfur dioxide and nitrogen are released into the air. These substances rise into the high atmosphere. They react with water and oxygen. This creates a more acidic rain. The rain with the high acid content falls. 

Ex Output:
sulfur dioxide ,nitrogen ,acidic rain ,water ,oxygen 


Ex Input:
People breathe and expel carbon dioxide. Engines produce carbon dioxide. Living things produce waste. Waste decomposes. Decomposition produces methane. Water evaporates. Water vapor joins the atmosphere. Carbon dioxide, water vapor and methane are greenhouse gases. 

Ex Output:
carbon dioxide ,methane ,water ,water vapor ,greenhouse gases 


Ex Input:
Warm water floats up from the ocean. A pocket of low pressure air is created near the surface of the ocean. Warm air from outside areas pushes into the low pressure area. The warm air keeps rising and forms clouds. The wind is getting fed moisture that evaporates from the ocean. This moisture causes the swirling air and clouds to grow bigger. As it gets bigger the wind rotates faster. 

Ex Output:

warm water ,low pressure air ,warm air ,clouds ,wind ,moisture ,swirling air