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

Example Input: Ionic compounds contain cations and anions rather than discrete neutral molecules.
Example Output: Ionic compounds contain cations and anions rather than what?

Example Input: 40 m/s north of the following represents the velocity of a moving object.
Example Output: Which of the following represents the velocity of a moving object?

Example Input: Most hormones are produced by the endocrine system.
Example Output:
Most hormones are produced by which human organ system?