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

[EX Q]: Solids are categorized by the forces holding the individual atoms, ions, or molecules together.
[EX A]: What is categorized by the forces holding the individual atoms, ions, or molecules together?

[EX Q]: Simple kind of diffusion do small hydrophobic molecules squeeze through lipid molecules.
[EX A]: What kind of diffusion do small hydrophobic molecules squeeze through lipid molecules?

[EX Q]: The soho spacecraft first started to operate in 1996.
[EX A]:
What year did the soho spacecraft first started to operate?