A key element of the Union victory in the Civil War was:
A. Splitting Confederate territory by controlling the Mississippi River.
Controlling the Mississippi River was a key strategic objective for the Union during the Civil War. The river was a major transportation route for the Confederacy, and its control would split the Confederacy in half, making it more difficult for Confederate forces to move troops and supplies.
The Union launched a series of campaigns to gain control of the Mississippi River, including the capture of New Orleans in 1862 and the siege of Vicksburg in 1863. The capture of Vicksburg was a major turning point in the war, as it gave the Union control of the entire Mississippi River and effectively split the Confederacy in half.
By controlling the Mississippi River, the Union was able to isolate Confederate forces in the west from those in the east, making it more difficult for them to coordinate their efforts. This ultimately contributed to the Union victory in the Civil War.