instruction:
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. 
question:
Fluid. Waste enters the kidneys. A processing moment in the kidneys let waste and fluid pass. Prevents larger molecules to pass. Fluid goes back to the bloodstream. Bad waste is removed. The final product is turned into urine. 
answer:
fluid ,waste;larger molecules;bad waste ,urine 


question:
A fuel source must produce heat. Heat is used to create steam. Steam will be used to power turbines. Turbines will work together with magnets to generate electricity. Electricity or moving electrons will then flow through wires. The wires will carry electrons to homes and businesses remotely. 
answer:
Fuel Source ,Heat ,Steam ,Electricity 


question:
Plants start growing on or near the rocks. The roots of the growing plants start to break up the rock. The plant acids dissolve the rock. The rock is broken down into smaller pieces. Erosion begins. 
answer:

plants ,rocks ; rock ,roots ,smaller pieces