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. 

A plant dies. Bacteria from the ground migrate to the plant material. Bacteria release enzymes onto the plant material. The enzymes break down the plant cells to simpler components. The bacteria absorb the resulting components. 
bacteria ,enzymes ,plant cells ,components 

Gather the ingredients for the cake. Mix the flour, sugar, egg, and water to make batter. Pour the mixture into a cake pan. Place the cake in the oven to cook. Take the cake out when it is cooked through. Let the cake cool. Serve the cake. 
flour ,sugar ,egg ,water ,batter ,cake 

Coal is loaded into the firebox. The boiler produces steam under high pressure. The steam generated in the boiler flows down into a cylinder. Just ahead of the wheels, pushing a tight-fitting plunger, the piston. The piston is connected to one or more of the locomotive's wheels through a kind of arm-elbow-shoulder joint called a crank and connecting rod. As the piston pushes, the crank and connecting rod turn the locomotive's wheels and power the train along. An outlet valve opens and the piston pushes the steam back through the cylinder and out up the locomotive's chimney. 

coal ,steam