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

Ex Input:
Surface tension is responsible for the fact that small insects can walk on water.

Ex Output:
Surface tension is responsible for the fact that small insects can do this on water?


Ex Input:
Ionic compounds contain cations and anions rather than discrete neutral molecules.

Ex Output:
Ionic compounds contain cations and anions rather than what?


Ex Input:
Digest food was the appendix used for in the past but is no longer needed for.

Ex Output:
What was the appendix used for in the past but is no longer needed for?