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How many planets are there in the solar system revolving around the sun?
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Which planet do people think is the most important one?
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From which field of science do we learn a lot about the planets?
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How long have astronomers studied the planets and other objects in space?
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What kind of new technology helped us a lot to study the planets?
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Which planet is the closest planet to the sun, Mercury, Mars, Venus or Jupiter?
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How long does it take Mercury to complete its orbit around the sun?
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How long does it take the Earth to rotate on its own axis once?
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Which planet is the easiest for people to see in the sky, Earth, Mercury, Venus or Jupiter?
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Which is the largest one of all the planets?