交作業。謝謝G兄！

據一項於12 月 8 日發表在Science Advances雜誌上的研究的合著者、土壤生態學家Matthew Bowker表示，中國長城的土壤表麵覆蓋著一層由微小無根植物和微生物組成的“活皮”，即生物結皮，這是該遺產地持久力的來源。

Based on Matthew Bowker - a soil ecologist and the  co_author of a research published on December 8th's Science Advances magazin , the soil on China's Great wall is coverd by a living skin, so called Biological soil crusts,  which are composed of  rootless micro  plants and microorganism.  This is why this heritage can last so long.