TOEFL Listening: TPO-TOEFL听力TPO - 5W278G80W1KRTI7ZR$

What points does the professor make about the bedrock underlying Manhattan? A. Its depth beneath the surface is the main factor when deciding where to build a skyscraper. B. It can fracture into large pieces from the weight of skyscrapers. C. It is used as an anchor for skyscrapers. D. Its depth beneath the surface affects the cost of building a skyscraper.