68. Given that all the following statements are true, which one, if added here, would provide the most effective transition from this paragraph to the next paragraph?
Your Answer is
Correct Answer is F
Explanation
The purpose of this paragraph is that the formation of noctilucent clouds requires dust. It is unclear how the particle source required by noctilucent clouds is provided in the next paragraph. Item F corresponds to a transitional role. There are irrelevant information in G/H/J.