Easy project idea?!?! URGENT?

It's just about 11:00 pm and I need an easy project idea that I can do before 6 a.m. tomorrow morning. The question that I have to answer is "Why did my civilization fail?" or something like that. Anyways, my civilization, well more of an era than a civilization is Feudal Japan. It failed because there was so much civil war, that when the mongols invaded, they didn't have any defense. Any help would be GREATLY appreciated!!!