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: Four electron groups orient themselves into what shape that has four faces? Answer: tetrahedron

A: Four electron groups orient themselves in the shape of a tetrahedron.
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Q: Question: What are the two main types of air pollutants? Answer: primary and secondary

A: There are two main types of air pollutants: primary and secondary. Most air pollutants come from burning fossil fuels. Some come from burning forests. Some are due to the evaporation of chemicals.
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Q: Question: A hair grows out of a follicle and passes through what before extending above the skin surface? Answer: epidermis

A:
Hair follicles are structures where hairs originate. Each hair grows out of a follicle, passes up through the epidermis, and extends above the skin surface.
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