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. 

Input: Consider Input: There is a fetus in the womb. They are born and are a baby. The baby grows into a child. Puberty turns the child into an adolescent. The adolescent becomes an adult. An adult becomes an elderly person. The elderly person dies. 

Output: fetus ,baby ,child ,adolescent ,adult ,elderly person 


Input: Consider Input: 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. 

Output: chorine ,heavy metals ,other chemicals 


Input: Consider Input: Something happens to produce a sound. The sound travels in waves. The sound waves hit an object. The object absorbs some of the sound waves. Some of the sound waves bounce off of the object. The reflected sound waves can be heard, though they have slightly different properties than the original sound. The sound continues to bounce off of things and produce echoes until it is totally absorbed or dissipated. 


Output: sound ; sound waves ,echoes