Undeclared wars.........................................
The main factor regarding the <span>United States dominating the world economy after the world war 2 was that it was a highly industrialized nation, and had not been "touched" by the war physically due to its isolation between two major oceans. </span>
Red-Bull, Sleep, and food!!
Barbarian groups were able to weaken the Byzantine Empire<span> because the empire itself had several unprotected areas for warring </span>groups<span> to invade.
Hope this helps!
-Sammy</span>
They are at the top because they are the wealthiest and have to most authority