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

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: Water is at the neutrality, 7 point on the ph scale.
Example Output: At what point is water on the ph scale?

Example Input: The epidermis of a leaf contains openings known as stomata, through which the exchange of gases takes place.
Example Output:
Which part of a leaf contains openings known as stomata, through which the exchange of gases takes place?