instruction:
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. 
question:
Energy builds up in the crust of the earth. The energy causes the fault lines give way. The earth's plates move. The energy radiates outward from the fault in all directions. The seismic waves shake the earth as they move through it. 
answer:
energy ,fault lines ,earth's plates ,seismic wave 


question:
Dissolution of limestone forms caves. Rain gets carbon dioxide from the air. When rain goes into soil it creates an acid. The acid dissolves the limestone along cracks. Some will dissolve enough to form caves. 
answer:
carbon dioxide ,rain ,acid ,limestone ,caves 


question:
You take some paper. The writing tools. You write a message describing what's on your mind. You put the letter into an envelope. You take the letter to the post office. Send it to its recipient. 
answer:

paper ,writing tool ,message ,letter 


