How did the arrival of the union reinforcements affect the outcome of the battle of gettysburg

C) Rome's centralized government was replaced by the rule of many kings and nobles. 
Rome at the time was an empire, not a democracy. It's far reaching expanse brought peace, stability and large area of semi-autonomous Roman territories, known as Pax Americana. As Rome fell, this empire was replaced by regional rulers asserting themselves across Europe, including kings and nobles.