The correct answers are:
B. The Battle of Atlanta significantly affected Confederate supply lines because Union forces destroyed a major transportation and railway hub in the South.
D. The Battle of Vicksburg significantly affected Confederate supply lines because Union forces took control of an important strategic location on the Mississippi River.
Both of these battles had a substantial impact on the Confederate supply lines. The Battle of Atlanta's destruction of infrastructure hindered the Confederacy's ability to transport troops and supplies, while the capture of Vicksburg by Union forces effectively divided the Confederacy and disrupted the flow of supplies along the Mississippi River.