❓ 题目 According to paragraph, which of the following is mentioned as a reason for the debate over formally defining the Anthropocene?
- A. A. The term was proposed by a Nobel laureate, making it scientifically controversial.
- B. B. Some scholars believe the start date should be earlier than the mid-20th century.
- C. C. The stratigraphic signatures are too subtle to be detected in sediment layers.
- D. D. The concept ignores the role of nuclear tests in creating radioactive isotopes.