❓ 質問 According to the passage, why is the keystone species concept considered controversial?
- A. A. It was based on experiments that were not replicated in other ecosystems.
- B. B. It is often applied too broadly, and keystone status may be context-dependent.
- C. C. It fails to explain the role of predators in controlling prey populations.
- D. D. It suggests that all species have equal importance in an ecosystem.