❓ 题目 According to the passage, what was the main finding of Robert Paine's experiments with Pisaster ochraceus?
- A. A) Physical factors are the primary determinants of community structure.
- B. B) Removing a top predator can lead to reduced species diversity in the ecosystem.
- C. C) Mussels are the keystone species in intertidal zones.
- D. D) Competition among species at the same trophic level is the main driver of diversity.