The Jungle Help.

[tactical]

I have an essay test coming up. I read this book, but it was very hard for me to understand. My teacher gave me the main points that the essay is going to be over. I was just wondering if any of you kind people here can help me out on these. The 3 points are the following:

1) Why did Upton Sinclair write this book?
2) What was he trying to prove?
3) What arguments about American society is he making and how?