Why was control of the Mississippi river an important goal of the union strategy in the west?

The union army could use the Mississippi for training purposes
Confederacy could no longer uses Mississippi river to carry its goods to see or use it to supply troops
The Mississippi river was key to connecting railroad system in the west industrial south
The confederacy would not be able to split union forces if they lost control of the river

Because the Confederacy heavily relied on the Mississippi River for transportation of goods, supplies, and communication, controlling the river was crucial for the Union to weaken the Confederate forces. By gaining control of the Mississippi River, the Union could effectively cut off the Confederacy's supply lines, isolate Confederate territories in the west from the rest of the Confederacy, and prevent the Confederacy from splitting Union forces. This strategic advantage played a significant role in the Union's overall military strategy in the West during the Civil War.