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

Ex Input:
Simple carbohydrates can be classified in terms of chain length.

Ex Output:
Which carbohydrates can be classified in terms of chain length?


Ex Input:
The discovery of ribozymes nullified the idea that all biological catalysts are proteins.

Ex Output:
What nullified the idea that all biological catalysts are proteins?


Ex Input:
Recrystallization is a process that can remove what, contaminants result when compounds are synthesized.

Ex Output:

Recrystallization is a process that can remove what, which result when compounds are synthesized?