TOEFL Listening: TPO-TOEFL听力TPO - D8J_0717F78ZT022R$

Why does the professor mention the Pleistocene epoch? A. To explain how sediments change during an ice age. B. To give an example of a well-defined geologic epoch C. To describe how certain environmental conditions affect erosion rates. D. To describe the factors that influence the naming of geologic epochs.