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

Example Input: Some materials have negative heats of solution; the dissolution of one of these solutes in water is called?
Example Output: Some materials have negative heats of solution; the dissolution of one of these solutes in water is called?

Example Input: The values of strangeness assigned to various particles are based on decay systematics.
Example Output: The values of strangeness assigned to various particles are based on what?

Example Input: 10 million years long can a large star be on the main sequence stage.
Example Output:
How long can a large star be on the main sequence stage?