Which river forms much of Tennessee's western border?

• A. The Mississippi River
• B. The Ohio River
• C. The Tennessee River
• D. The Missouri River

Answer: (A)

The key idea is identifying which river serves as a natural boundary for Tennessee. The Mississippi River forms much of the state's western border, running along the edge of Tennessee to separate it from Arkansas and Missouri. This river is widely known for outlining several state borders in the region, making it the primary western boundary for Tennessee.

The other rivers don’t fit this role: the Ohio River runs more along Kentucky’s border with Indiana and Illinois, not Tennessee’s western edge; the Tennessee River flows through eastern Tennessee but does not define the western boundary; and the Missouri River is far to the west and does not touch Tennessee.