Huckleberry Finn prompt?

For my English cl, we're supposed to write an essay on Huckleberry Finn about a prompt of our choice. I chose my prompt to be "How does the theme of moral education vs formal education pertain to Huck Finn?" Well, I did my annotated bibliography, which I've already turned in, based on this prompt, forgetting that our essay is supposed to either 1) be persuasive or 2) show cause and effect in Huckleberry Finn. The prompt I chose doesn't really do either of those. I was just wondering if anyone has any ideas as to how I can tweak my prompt so that it does do one of those? I have a few ideas, but none of them really seem to be 5-page essay material. Thanks so much to all who answer!