How did America expand its territory in 1800s and how did that led to the civil war and reconstruction?

Slavery in the Western Territories. To many nineteenth century Americans, the expansion of slavery into Western territories caused a great deal of controversy. ... The federal government, hoping to prevent a civil war, temporarily resolved the issue with compromises.

Explanation:

c is the correct answer for this question.

united states reinforcements contributed greatly to three allied victories in france at: cantigny (first major american battle), argonne (the largest in the united states military history, involving 1.2 million american soldiers), and château-thierry (one of the first actions under general pershing).