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: A stream or river must occur. Through erosion, the stream cuts into the soil and bedrock. Through continuous erosion, a deep gash is cut through. After many years the river may dry up. A dry ravine is left. 

Answer: stream; river ,soil; bedrock ,gash ,dry ravine 


Question: A butterfly lays an egg. A larvae matures inside of the egg. The caterpillar hatches from the egg. The caterpillar eats and grows. The caterpillar spins a coccoon around itself and forms into a pupa. The butterfly forms inside of the coccoon. The mature butterfly emerges from the coccoon. The butterfly mates. The female butterfly lays eggs. 

Answer: egg ; eggs ,larvae ,caterpillar ,pupa ,butterfly 


Question: Water comes through a filter. The filter has small pores to catch pollutants. The filter will catch chlorine, heavy metals, and other chemicals. The filter allows water and mineral ions like fluoride to pass through. The water on the other side of the filter is much cleaner. 

Answer:
chorine ,heavy metals ,other chemicals