TOEFL Listening: TPO-TOEFL听力TPO - C3FY30878J8NW8MMR$

Why does the professor mention limestone? A. To support a theory about why most Mayan structure are well preserved B. To point out a difference between Mayan structure in Guatemala and those in other areas C. To suggest a reason why certain vegetation stands out in infrared images D. To explain why it is difficult to locate ancient buildings in jungles