Earth
Ruby and sapphire are gem forms of which mineral?
More Questions from Earth
How many days a year is the sun invisible at the North Pole?
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What is the hard, dark substance found in the ground that is mined for fuel?
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What is the trapping of the sun's solar energy and radiation called?
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What is a person called who specializes in the physical structure and process of the earth?
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What is it called when a plant produces two kinds of sex cells?
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