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: Prophase, the chromosomes become visible. Centrioles separate to move to opposite poles. Metaphase, the chromosomes line up in the center. Anaphase, the chromatids separate. Are pulled apart. Telophase, the chromosomes gather at opposite poles. Two new nuclear membranes form. The cell membranes pinch. Divide into two individual cells. 

SOLUTION: chromosome ,centriole ,spindle fiber ,chromatid ,nuclear membrane 

PROBLEM: People separate different materials to be recycled. The recyclable materials go to a recycling center. The recycling center further separates the materials. Large equipment compacts the materials into bales. The recyclable materials are shipped to other recycling centers. The other recycling centers further process the materials that center specializes in. The materials are purchased by manufacturers. The manufacturers process the recycled materials the same way they would use new materials. The recycled materials are incorporated into new products. 

SOLUTION:
recyclable materials ; the materials ,bales ,bales