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

[EX Q]: Particle accelerators can nuclear fusion in stars be simulated.
[EX A]: How can nuclear fusion in stars be simulated?

[EX Q]: Intraplate earthquakes occur because solid lithosphere travels on a round planet.
[EX A]: What occur because solid lithosphere travels on a round planet?

[EX Q]: Cloud of these can make a shadow on the ground during the day.
[EX A]:
Which of these can make a shadow on the ground during the day?