Which statement best describes the contributions of Fredrick Douglas during the civil war?
1. Douglas was an abolitionist who served the Union in the 54th Massachusetts Regiment.
2. Douglas was an abolitionist who formed the flying squadron known as the Tuskegee Airmen.
3. Douglas was an abolitionist who encouraged the union to allow African Americans to enlist.
4. Douglas was an abolitionist who helped enslaved people escape through the Underground Railroad.