❓ 题目 According to the passage, which of the following statements about keystone species is TRUE?
- A. A. Keystone species are always the most abundant organisms in their ecosystem.
- B. B. The term 'keystone species' was coined by Robert Paine after his experiment with beavers.
- C. C. The removal of a keystone species can lead to a cascade of secondary extinctions.
- D. D. Keystone species have the same impact in every ecosystem they inhabit.