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

Example Input: The behavior of ideal gases is explained by kinetic molecular theory.
Example Output: The behavior of ideal gases is explained by what theory of gases?

Example Input: Mercury is not a solid even at room temperature.
Example Output: Which metal is not a solid even at room temperature?

Example Input: In hornworts, the horns are the sporophytes that rise up from the leaflike gametophyte.
Example Output:
In hornworts, the horns are the sporophytes that rise up from what?