❓ 質問 According to the passage, which of the following best describes the main effect of removing *Pisaster ochraceus* in Paine’s experiments?
- A. A) Physical factors became more important in structuring the community.
- B. B) Competitive mussels increased, leading to a loss of species diversity.
- C. C) Top-down regulation strengthened, allowing more species to coexist.
- D. D) The starfish’s abundance decreased, but the ecosystem remained stable.