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

[EX Q]: 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.
[EX A]: 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?

[EX Q]: Some meteorites are made of iron and nickel and are thought to be very similar to the core of the earth.
[EX A]: Some meteorites are made of iron and nickel and are thought to be very similar to what part of the earth?

[EX Q]: Microscopes were first developed in the early 1600s by eyeglass makers.
[EX A]:
Microscopes were first developed in the early 1600s by this trade?