Those factors were:
city-states
the drawing of political borders
divide and rule policies
During the start of the civil war, the confederate side was gaining victory because the union at first did not allow slaves to help fight until president Lincoln finally signed the emancipation proclamation which allowed the slaves to help fight, gaining back the victory of the union. hope this helped.
The correct answer is: "railroads".
Railroads flourished during the 19th century and enabled to travel long in-land distances much quicker than before. They were also one of the main factors that triggered the industrial revolution, as quick transportation reduced production costs and brought important efficiency gains for industries, for instance, in coal mining, and contributed to the development of mass production systems.
The answer is <span>"was the first time the Constitution defined what a citizen is"</span>
