TOEFL Listening: ETS-TOEFL听力机经 - 5GON40A6CKO03955P$

Why does the professor the amount of sunlight that Titan receives? A. To acknowledge that the differences between Earth and Titan are significant. B. To out point that many chemical processes are dependent on the presence of sunlight. C. To explain why it is surprising that pools of liquid are present on Titan's surface. D. To point out a similarity between Titan and Earth's moon.