❓ 题目 According to the passage, which of the following best explains why reducing nutrient inputs may not restore a shallow lake to its clear-water state?
- A. A) The clear-water state is always more stable than the turbid state.
- B. B) The turbid state is maintained by self-reinforcing feedback mechanisms.
- C. C) Engineering resilience is more important than ecological resilience for lakes.
- D. D) Nutrient inputs are not the primary cause of the shift to turbidity.