Bacteria are sosmall that a single round one of acommon type is about1/25,000 of an in ch across when thesebacteria aremagnified 1,000 times, they look only aslarge as apencilpoint.

细菌是这样小，一种普通类型的圆形细菌直径大约只有1/25，000英寸。 这种细菌放大一千倍看起来也只有铅笔尖那么大。

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Under a microscope, the scientists discovered the holes were too perfectly round to have been caused by bacteria.

BBC: Prehistoric dentistry evidence found

The surviving bacteria would "level up" and provide the player with a better challenge during the next round.

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