TASK DEFINITION: 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. 
PROBLEM: Warm air from the surface rises into the higher cold air. The water vapor in the air is condensed. The condensed water and dust forms a cloud. Wind in the cloud bounces the water droplets around. The bouncing droplets join together. The bigger droplets get heavy. The heavy droplets fall. As they fall, they join with more moisture in the air. The droplets get larger. Rain falls. 

SOLUTION: warm air ,water vapor ,condensed water ,dust ,cloud ,water droplets ; droplets ,moisture ,rain 

PROBLEM: Algae and plankton die. The dead algae and plankton end up part of sediment on a seafloor. The sediment breaks down. The bottom layers of sediment become compacted by pressure. Higher pressure causes the sediment to heat up. The heat causes chemical processes. The material becomes a liquid. Is known as oil. Oil moves up through rock. 

SOLUTION: algae ,plankton ,sediment ,material ,oil 

PROBLEM: A fuel is heated in an oven. Above the oven is a tank of water that is sealed. The tank of water begins to boil above the oven. A the water boils steam is created. The steam is denser than air so it needs a place to go. The steam is forced out of the tank and into a piston. The piston moves up. The valve of the piston closes. The valve on the next piston opens. The steam fills the next piston, driving it up, and the other one down. 

SOLUTION:
fuel ,water ,steam 

