TOEFL Reading: ETS-TOEFL阅读机经 - 44556L31C68N_793L$

What can be inferred from paragraph 6 about the role that gravity on the outer planets plays in their having low densities? A. The forces of gravity from the outer planets increase the speed of the solar winds, causing the winds to carry away the heavier, denser elements. B. The outer planets' strong gravities capture low-density ices from the outer reaches of the solar system. C. Gravity on the outer planets is strong enough to prevent lighter elements from escaping. D. The strong gravity on the outer planets results in high-velocity impacts with nebular debris, causing their denser elements to be carried away into space.