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At one time, the animals present in these fossil beds were assigned to various modern animal groups, but most paleontologists now agree that all Tommo 阅读全文
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Contrary to the arguments of some （that much of the pacific was settled by Polynesians accidentally marooned after being lost and adrift）, it seems re 阅读全文
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Only recently have investigators considered using these plants to clean up soil and waste sites that have been contaminated by toxic levels of heavy m 阅读全文
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Perhaps, like many contemporary peoples, Upper Paleolithic men and women believed that the drawing of a human image could cause death or injury, and i 阅读全文
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The transition from forest to treeless tundra on a mountain slope is often a dramatic one. Within a vertical distance of just a few tens of meters, tr 阅读全文
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Stories (myths) may then grow up around a ritual. Frequently the myths include representatives of those supernatural forces that the rites celebrate o 阅读全文
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Thus a proportion of the total volume of any sediment, loose or cemented, consists of empty space. Most crystalline rocks are much more solid; a commo 阅读全文
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生物信息学 Cell theory:7个要点 All known living things are made up of one or more cells. All living cells arise from pre-existing cells by division. The cell 阅读全文