Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: The mesopause is at the top of the mesosphere.

Answer: What is at the top of the mesosphere?


Question: The best way humans can conserve water is to use less.

Answer: What's the best way humans can conserve water?


Question: While the numerical aperture can be used to compare resolutions of various objectives, it does not indicate how far the lens could be from the specimen.

Answer:
While the numerical aperture can be used to compare resolutions of various objectives, it does not indicate how far the lens could be from the what?