In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

Q: Question: What is the hollow and muscular balloon-shaped organ that collects urine? Answer: urinary bladder

A: The urinary bladder is the hollow and muscular balloon-shaped organ that collects urine.
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Q: Question: All cells undergo what during a lifetime, but when this process is out of control, cancer results? Answer: cell division

A: All cells undergo cell division during a lifetime, but when this process is out of control, cancer results.
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Q: Question: What causes light to refract? Answer: slowing down

A:
Slowing down causes light to refract.
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