❓ 题目 According to the passage, which of the following is a key reason why some scientists oppose formalizing the Anthropocene as a new geological epoch?
- A. The proposed start date is not supported by any physical evidence in rock layers.
- B. Human impacts on Earth's systems began earlier than the mid-20th century, making a single start point problematic.
- C. The Great Acceleration was primarily a cultural phenomenon, not a geological one.
- D. Radioactive isotopes from nuclear tests are too rare to serve as a reliable marker.