The president selects cabinet members to give regional balance to his administration.
From the late eighth through the end of the ninth century, something unknown happened to shake the Maya civilization to its foundations. One by one, the Classic cities in the southern lowlands were abandoned, and by A.D. 900, Maya civilization in that region had collapsed.
The Shia Islamic sect belives that Ali is the true successor of the prophet Mohammed
they represent the states fairly. The house represents by population, since the big states think they should at least get an advantage of being big. The senate represents small states, where every state gets the same amount of votes instead of different amounts like in the house. they both are a compromise for the states