TOEFL Listening: TPO-TOEFL听力TPO - I1E1Y4K7FSY7C076R$

What does the professor mainly discuss? A. How the seafaring skills of Polynesians resembled those of the Vikings B. How Pacific Islanders were able to navigate without instruments C. How the patterns of stars differ to the north and south of the equator D. How navigational instruments developed over time