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

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: A vapor light produces visible light by electroluminescence process.
Example Output: A vapor light produces visible light by what process?

Example Input: The term volume means the amount of space matter takes up.
Example Output:
What term means the amount of space matter takes up?