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: Batteries are put in a flashlight. The flashlight is turned on. Two contact strips touch one another. A circuit is completed between the batteries and the lamp. The lamp in the flashlight begins to glow. The reflector in the flashlight directs the lamp's beam. A straight beam of light is generated. The flashlight is turned off. The circuit is broken. The beam is no longer visible. 

SOLUTION: batteries ,flashlight ,lamp ,straight beam of light ; beam ,circuit 

PROBLEM: Bacteria enters the body. Bloodstream. Cells in the body are attacked. Cells are killed. Different kinds of sickness are formed. 

SOLUTION: bacteria ,cells ,sickness 

PROBLEM: Fluid. Waste enters the kidneys. A processing moment in the kidneys let waste and fluid pass. Prevents larger molecules to pass. Fluid goes back to the bloodstream. Bad waste is removed. The final product is turned into urine. 

SOLUTION:
fluid ,waste;larger molecules;bad waste ,urine