3. How is it that, though the moon turns round on its axis, we never see its other side?
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4. Why is hard water very unsuitable for cooking and washing?
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5. What celebrated work was written in a week to defray the cost of the funeral of the author's mother?
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6. How did the thistle come to be the emblem of Scotland?
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7. What sea has water so thick that you can move in it with difficulty?
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