TOEFL Listening: TPO-TOEFL听力TPO - SUYH1348FWW7181FR$

Why does the professor talk about the breaking apart of Earth's continents? A. To give another example of how uranium-lead dating might be useful B. To explain how the Grand Canyon was formed C. To demonstrate how difficult uranium-lead dating is D. To disprove a theory about the age of Earth's first mountain ranges