Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Q: Question: Matter can exist either as a pure substance or as a combination of what? Answer: different substances

A: The properties of matter, both physical and chemical, depend on the substances that matter is made of. Matter can exist either as a pure substance or as a combination of different substances.
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Q: Question: As a polycrystalline material solidifies, grains with irregular shapes form. the interfaces between grains constitute grain what? Answer: boundaries

A: Grain boundaries. As a polycrystalline material solidifies, grains with irregular shapes form. The interfaces between grains constitute grain boundaries. (Squares represent unit cells within grains.
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Q: Question: What is the name of pluto's moon? Answer: charon

A:
Pluto and its moon, Charon, are actually two objects.
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