❓ 質問 According to the passage, what is the main reason for the controversy over formally defining the Anthropocene as a geological epoch?
- A. A. The lack of scientific evidence for human impact on Earth's systems.
- B. B. The difficulty in establishing a precise and globally consistent starting point.
- C. C. The opposition from atmospheric chemists like Paul Crutzen.
- D. D. The absence of any distinct markers in geological strata.