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

Q: Air quality is a measure of pollutants in the air.

A: Air quality is a measure of what in the air?
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Q: Some meteorites are made of iron and nickel and are thought to be very similar to the core of the earth.

A: Some meteorites are made of iron and nickel and are thought to be very similar to what part of the earth?
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Q: Two water molecules contain 4 hydrogen atoms and 2 oxygen atoms.

A:
Two water molecules contain 4 hydrogen atoms and how many oxygen atoms?
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