1、 Because they lack oxygen, marsh sediments are high in sulfides that are toxic to most plants.
由于它们缺乏氧气，沼泽沉积物中的硫化物含量很高，而硫化物对大多数植物都有毒。
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2、 The Holocene Epoch is characterized by different sediments, ones that form when the climate is warmer.
全新世时期的特征为不同的沉积物，它们在气候变暖时形成。
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