Overall, the greatest accomplishment of the united states during the civil war era was:
a) to be able to claim it was still one country.
b) to resolve most of the differences between the sections peacefully.

wwii

explanation:

no statements but ok.

the statement that best describes the idea of manifest destiny that was used in the 19th century would be that "it was fate that the united states would continue to  expand westward," since people thought the us was "destined" to do so.