❓ 문제 According to the passage, which of the following is TRUE about the keystone species concept?
- A. A. It was first proposed by Robert Paine based on experiments in tropical rainforests.
- B. B. It applies exclusively to predatory species like starfish and elephants.
- C. C. It is a useful but sometimes overused idea that needs empirical validation.
- D. D. It is universally accepted without any criticism from ecologists.