A rich and complex community that is kept in balance 这个丰富多样的群落想要保持生态平衡
..requires some complex calculations. 需要一些复杂的计算
Jungles are complex places... 丛林错综复杂
shows us once again how complex and surprising the underground world can be. 再一次向我们展示了地底世界 是多么的复杂和惊人