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. 

[Q]: Solar panels actually comprise many, smaller units called photovoltaic cells. Photovoltaic simply means they convert sunlight into electricity.). Many cells linked together make up a solar panel. Each photovoltaic cell is basically a sandwich made up of two slices of semi-conducting material, usually silicon : . Manufacturers "dope" silicon with other materials, giving each slice of the sandwich a positive or negative electrical charge. This adds extra electrons, with a negative charge, to that layer. Meanwhile, the bottom layer gets a dose of boron, which results in fewer electrons, or a positive charge. This all adds up to an electric field at the junction between the silicon layers. When a photon of sunlight knocks an electron free, the electric field will push that electron out of the silicon junction. A couple of other components of the cell turn these electrons into usable power. 
[A]: sunlight ,electrictiy ,solar panel ,electric field 


[Q]: Water is exposed to heat energy, like sunlight. The water temperature is raised above 212 degrees fahrenheit. The heat breaks down the molecules in the water. These molecules escape from the water. The water becomes vapor. The vapor evaporates into the atmosphere. 
[A]: water ,sunlight ,molecules ,vapor 


[Q]: Fuel produces heat. Water is boiled to make steam. Steam spins turbine. Generator is turned. Makes electricity. Electricity transfers to transformers. Produces the correct voltage. 
[A]:
fuel ,heat ,water ,steam ,turbine ,generator ,electricity ,voltage