题目解析:
要求回到Frederick Clements在第二段中关于ecological communities的观点。文章整段都在描述他的观点,因此使用排除法。
A选项、D选项利用关键词balanced定位到:
This "climax" community was, in Clements's mind, the most well-balanced, integrated grouping of species that could occur within that particular region.
A选项出现的only when属于极端程度词,文章中没有提到这层意思,排除;对应句中其中提到这是一种most well-balanced, integrated grouping of species that could occur within that particular region. 其表达的最高级别的平衡,融合就是D选项中所说的maximum level of balance,因此答案为D选项。
B选项、C选项根据climatic climax定位到段落第二句:
He held that within any given region of climate, ecological communities tended to slowly converge toward a single endpoint, which he called the ""climatic climax.""
其中提到climatic climax是一个single endpoint,并没有提到之后就开始decline,属于偷换概念;C选项的all属于极端程度词,原文中没有提到所有的climates都有类似的climax communities这个信息;