交作业, 谢谢！

据一项于12 月 8 日发表在Science Advances杂志上的研究的合著者、土壤生态学家Matthew Bowker表示，中国长城的土壤表面覆盖着一层由微小无根植物和微生物组成的“活皮”，即生物结皮，这是该遗产地持久力的来源。

According to a study published in Science Advances on Dec. 8th, soil ecologist Matthew Bowker, one of the study's co-authors, states that the soil surface of the Great Wall has a "living skin," meaning tiny plants without roots and microorganisms covering the soil. This is also known as a biological crust that preserves the long-standing cultural heritage.