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. 

Example Input: During evaporation the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air. Water vapor in the air gets cold and changes back into liquid, forming clouds, which is called condensation. Precipitation occurs when so much water has condensed that the air cannot hold it anymore. Water falls back to the earth in the form of rain, hail, sleet or snow. When water ends up on land, it will either soak into the earth and become part of the "ground water" for animals or plants to drink. It may also run into the oceans, lakes, or rivers where the cycle starts again. 
Example Output: water ,vapor; steam; water vapor ,clouds ,rain ,hail ,sleet ,snow 

Example Input: Chemical reactions in the battery causes a build up of electrons at the anode. This results in an electrical difference between the anode and the cathode. The electrons wants to rearrange themselves to get rid of this difference. The electrons go to the cathode. Electricty is created. 
Example Output: electricity ,electrons at the anode ,electrons at the cathode 

Example Input: Water flows by rocks. Chemicals are in the waters. Chemicals react with rocks. Rocks change to a different kind of rock. Oxygen in the air reacts with rocks. Rocks change to a different kind of rock. 
Example Output:
water ,rocks ,chemicals ,oxygen