单选题 Some scientists have suggested that earth is a kind of zoo or wildlife______for intelligent space beings, like the wilderness areas we have set up on earth to allow animals to develop naturally while we observe them.

【正确答案】 D
【答案解析】[解析] 本题空格处讲的是野生动植物保护区，应用wildlife reserve是野生动植物保护区(具体概念)，而wildlife conservation是对野生动植物的保护(抽象概念)。maintenance意为“维护，保持”；storage意为“贮藏(量)”。可见D项为正确答案。