TOEFL Listening: ETS-TOEFL听力机经 - 7YKTNV31AEPWX6Z4P$

Why does the professor discuss the Aspero site in Peru? A. To provide evidence of an ancient Peruvian culture's knowledge of irrigation techniques B. To point out that the Aspero pyramids are different from those found at other Norte Chico sites C. To explain a belief about Peruvian history that was later challenged D. To clarify which of the twenty residential centers in the Norte Chico region was the largest