题目内容：
To survive, a non-human species must be too ________ to be thoroughly captured, too ________ to be noticed, or too immutable to be changed.
参考答案：
答案解析：
单选题：To survive, a non-human species must be too ________ to be t
- 题目分类：GRE
- 题目类型：单选题
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