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

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


[Q]: If a substance has a ph value greater than 7,that indicates that it is base.
[A]: If a substance has a ph value greater than 7, what does it indicate?


[Q]: Most of the gray matter is on the surface of the brain, surrounding white matter.
[A]:
Most of the gray matter is on the surface of the brain, surrounding what other type of matter?