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: Light enters the eyes. The lens focuses light through the vitreous humor. The cornea focuses through the eye's internal lens. The retina receives the image. The retina transforms this image into electrical impulses. The impulses travel along the optic nerve to the brain. The brain decodes the impuses. 

Answer: image ,electrical impulses 


Question: Food enters the body. The food is broken down. Sugars from the food enter the bloodstream. Blood sugar must be within a particular range to avoid damaging many organs. Sometimes the brain tells the pancreas the blood sugar (glucose) is too low. The pancreas releases glucagon to change the blood sugar to a better level. Sometimes the brain tells the pancreas the blood sugar (glucose) is too high. The pancreas releases insulin to change the blood sugar to a better level. 

Answer: food ,sugars ,blood sugar ,glucagon ,insulin 


Question: Bacteria changes nitrogen into ammonium through fixation. The nitrification process is where ammonium gets changed into nitrates by bacteria. Plants absorb the nitrates from soil into their roots through assimilation. When plants die, fungi and bacteria turn nitrogen back into ammonium through ammonification. The denitrification process pushes extra nitrogen from soil into the air. The cycle repeats from step 1. 

Answer:
nitrogen; nitrates ,ammonium ,plant ,extra nitrogen