A mockingbird symbolizes innocent. Harper Lee probably has Jem and Scout hear a mockingbird as they're walking to their school alone because through the story they symbolize the innocence of youth, sheltered in their community. The action of the novel has them experiencing things far beyond what they ever have before and trying to maintain their innocence.
I don't believe in the American Dream, because if you look outside your window, there are so many people in broken down houses, most without a house. Sleeping in cars, sleeping on a friend's couch, homeless shelters, foster care. I believe it would be possible if the rich gave more to the poor. I think those who believe in it have their heart in the right place, but to be honest, there's nothing much they can do unless they convince the government to tax the rich higher taxes, and give the extra to the poor. It is foolish to believe America will ever be what the American Dream stands for. Honestly, when somebody has money, they don't want to give it to anybody else. Keep it themselves.
Hope this helps!
-Belle
