Final answer:
The anthem that African Americans sang during the Civil War was the "Star-Spangled Banner."
Step-by-step explanation:
The anthem that African Americans sang during the Civil War was the "Star-Spangled Banner." This anthem, written by Francis Scott Key in 1814, became a symbol of American patriotism and freedom. While it wasn't exclusively sung by African Americans, they too embraced and sang this anthem as a way to express their hopes for equality and freedom.