TOEFL Listening: ETS-TOEFL听力机经 - 3J5_8W11J3QD7T3RP$

What effect of Jupiter's gravitational force does the professor emphasize? A. It causes variations in the shape of Io's surface B. It causes variations in Io's rate of spin C. It causes ocean levels on Io to rise and fall D. It keeps the same side of Io always facing Jupiter