大部分在古生代岩层中发现的化石都是没有脊骨的无脊椎动物，例如珊瑚、软体动物和三叶虫。
Most of the fossils seen in Paleozoic rocks are invertebrate animals lacking backbones, such as corals, mollusks and trilobites.
大部分在古生代岩层中发现的化石都是没有脊骨的无脊椎动物，例如珊瑚、软体动物和三叶虫。
Most of the fossils seen in Paleozoic rocks are invertebrate animals lacking backbones, such as corals, mollusks and trilobites.
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