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1. C (Several hundred million years ago, plants similar to modern ferns covered vast stretches of the land...)
2. A (Several hundred million years ago, plants similiar to modern ferns covered vast stretches of the land. Some were as large as trees, with giant fronds bunched at the top of trunks as straight as pilliars. Others were...)
3. D (Several hundred million years ago....where giant amphibians swam)
4. B genuine: thật, xác thực, chính cống
5. A (Such traces are most commonly found in shale and sandstone rocks weiged between coal beds)