please i'm really begging hee it's my last thing to do for the day...Please help with the reason/explanation for the evidence above

A major supply route that divided the South.

Explanation:

During the American Civil War both the Confederacy and the Union fought battles to control the Mississippi river which in effect divided the South.

For the Confederacy, the river was needed to keep up the war effort as manpower and materials needed by the states to the East to survive and fight were usually situated in the west of the river in Texas, Arkansas and Western Louisiana.

For the Union, they needed control of the River to isolate the Eastern Confederacy who were reliant on the west and defeat them.

They also wanted to set up Navel bases where they could land armies and attack the Confederacy with ease. They finally wrestled control of this river from the Confederates on July 4, 1863 when Vicksburg fell to the Union.