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新概念优美背诵短文50篇 Unit14:A Rare Fossil Record 14 A Rare Fossil Record The preservation of embryos and juveniles is a rate occurrence in the fossil record. The tiny, delicate skeletons are usually scattered by scavengers or destroyed by weathering before they can be fossilized. Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because, as...