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

[EX Q]: Control rods play an important role in the modulation of the nuclear chain reaction.
[EX A]: What play an important role in the modulation of the nuclear chain reaction?

[EX Q]: The discovery of ribozymes nullified the idea that all biological catalysts are proteins.
[EX A]: What nullified the idea that all biological catalysts are proteins?

[EX Q]: Paper cup object has the greatest flexibility.
[EX A]:
Which object has the greatest flexibility?