Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Q: A concave lens is thicker at the edges than it is in the middle.

A: What type of lens is thicker at the edges than it is in the middle?
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Q: One of the properties of an air mass is that an air mass has similar temperature and moisture properties throughout it.

A: Which of the following is true regarding the properties of an air mass?
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Q: The urinary bladder is the hollow and muscular balloon-shaped organ that collects urine.

A:
What is the hollow and muscular balloon-shaped organ that collects urine?
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