How is the American Government Organized and their functions?

- I have to write a 5 paragraph essay and I need help researching.

- Do you know a website I can get information?

P.S ; I do not have a book. I'm taking an online class and I have to start/finish it by tomorrow. I have to take the final tomorrow also.

Please Help Me!

http://bensguide.gpo.gov/

http://mrnussbaum.com/government/