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. 

You breathe in. Diaphragm and other muscles expand to allow room for your lungs to fill. The air flows into the narrow bronchioles in the lungs. From the bronchioles to the alveoli. The oxygen enters into the bloodstream. Is switched with the carbon dioxide in the bloodstream. The carbon dioxide enters through the alveoli. Through the narrow bronchioles. Into the lungs. The carbon dioxide is exhaled out of the body. 
air ,oxygen ,carbon dioxide 

The cornea and lens refract light into a small image. Shine it on the retina. The retina's rods and cones convert it to electrical pulses. The optic nerve carries electrical pulses through the optic canal. Nerve fibers end in the lateral geniculate nucleus and the visual cortex. 
light ,small image ,retina's rods and cones ,electrical pulses 

A seed is in soil. The seed germinates. The plant grows roots. The plant grows out of the ground. The plant gets bigger. The plant flowers. The flower produces fruit. The fruit releases seeds. The plant dies. 

seed ,plant ,roots ,flowers ,fruit