Final answer:
General Ulysses S. Grant captured Fort Donelson and Fort Henry to gain control over the Cumberland and Tennessee rivers during the Civil War, as part of the Union's strategy to divide the Confederacy.
Step-by-step explanation:
General Ulysses S. Grant gained control of the Cumberland and Tennessee rivers with the capture of Fort Donelson and Fort Henry. These strategic victories were crucial in the Western Theater of the American Civil War. The captures secured the Union's control over these vital waterways, which were key to the logistics and movement of forces. This was part of a broader strategy to divide the Confederacy by gaining control over the Mississippi River.
The fall of these forts marked significant Union victories and were instrumental in further pushes into Confederate territories, including the pivotal siege and capture of Vicksburg, which handed the Union forces complete control over the Mississippi River.