The principle of government by law.
After the Battle of Antietam in 1862, President Abraham Lincoln announced his intention of freeing all slaves in the Confederacy.
Answer:
The advent of civilization depended on the ability of some agricultural settlements to consistently produce surplus food, which allowed some people to specialize in non-agricultural work, which in turn allowed for increased production, trade, population, and social stratification.
I think the correct answer is C