Final answer:
General Ulysses S. Grant's leadership helped to preserve the Union at the end of the Civil War.
Step-by-step explanation:
The leadership of General Ulysses S. Grant helped to preserve the Union at the end of the Civil War.
Grant played a crucial role in multiple Union victories, such as the Battle of Vicksburg and the defeat of General Robert E. Lee at Gettysburg.
His military strategies and determination were key in weakening the Confederate forces and ultimately leading to their surrender.