5. Which of the following is true according to this passage?
(A) The more diverse a natural system is, the more stable.
(B) Maximum output of a single crop may be harmful to the whole system.
(C) Human intervention in a natural system is often counterproductive.
(D) All of the above

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統計: A(0), B(0), C(0), D(2), E(0) #1180277