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

Input: Consider Input: The combustion of propane gas produces carbon dioxide and water vapor.

Output: The combustion of propane gas produces carbon dioxide and what else?


Input: Consider Input: Most hormones are produced by the endocrine system.

Output: Most hormones are produced by which human organ system?


Input: Consider Input: High per capita use of resources means the ecological footprint of the united states is large.


Output: High per capita use of what means the ecological footprint of the united states is large?