❓ 题目 According to the passage, which of the following is cited as evidence for placing the start of the Anthropocene in the mid-20th century?
- A. A. Early signs of deforestation and species extinction
- B. B. The presence of radioactive isotopes and microplastics in geological layers
- C. C. The beginning of the Holocene epoch
- D. D. Natural volcanic activity and asteroid impacts