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: Coal is mined out of the ground. Coal is pulverized into fine powder. The coal is mixed with hot air. The coal and hot air are blown into a boiler. The coal and hot air burn over a fire. Highly purified water is pumped through pipes in the boiler. The water turns into steam. The steam presses against turbines. The turbines spin. Electricity is produced. 

SOLUTION: coal ,hot air ,water ,steam ,electricity 

PROBLEM: Bees find a place for the hive, such as a rock crevice or tree branch. Bees gather nectar from flowers. The bees evaporate the nectar by passing it back and forth to each other. The evaporation turns the nectar into sugary honey. The bees chew the honey until it turns into moldable wax. The bees mold the wax into hexagonal (six sided) cylinders. Thousands of these hexagonal cylinders put together form the hive. 

SOLUTION: bees ,nectar ,honey ,wax ,cylinders ,hive 

PROBLEM: An owl leaves his nest. The owl flys out into the night. The owl looks down at the ground. The owls keen eyesight allows him to see in the dark. The owls sensitive hearing allows him to locate hidden prey. The owl swoops down. The owl catches a mouse in his talons. 

SOLUTION:
owl ,mouse