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

Example Input: Oxygen gas is given off by plants.
Example Output: Which gas is given off by plants?

Example Input: Cancer occurs most often in adults over fifty age.
Example Output: Cancer occurs most often in adults over what age?

Example Input: Spontaneous process kind of process occurs without the need for a continual input of energy from some external source.
Example Output:
What kind of process occurs without the need for a continual input of energy from some external source?