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

Input: Consider Input: Some compounds form rigid frameworks called crystals.

Output: Some compounds form rigid frameworks called what?

Input: Consider Input: Particle accelerators can nuclear fusion in stars be simulated.

Output: How can nuclear fusion in stars be simulated?

Input: Consider Input: Trichomoniasis is cause by a protozoa.
Output: Trichomoniasis is cause by what type of pathogen?