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

Q: The opening in the front of the eye is called pupil.

A: What is the opening in the front of the eye called?
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Q: The newest, outer layers of secondary xylem are called sapwood.

A: What are the newest, outer layers of secondary xylem called?
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Q: Nuclei with even numbers of protons, neutrons, or both are more likely to be stable.

A:
Nuclei with even numbers of protons, neutrons, or both are more likely to be this?
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