The migration patterns of a group of people, the way those people affect their land, and the way their land affects those people
911 was one of the most tragic event in modern history to happen what is believed to happen is that two plan crashed into the twin tower cause them to fall and the other plan would have crashed into the White House if some of the passengers had not taken upon them self to turn the plan a different way to stop it from hitting the White House
In a confederacy, there is no such thing as a strong central government and the purpose of a confederacy is to protect the states in it from foreign incursion, not to solve domestic problems which are all handled by individual local governments. The articles of confederation established such a confederacy of the first states and they needed the constitution in order to turn into a federation.
Mars and mercury is right :)