Harriet Tubman was born a slave in Maryland around 1820. She escaped to the North in 1849, but she immediately returned to the South to help other slaves escape. Doing this was no easy task. Tubman used the Underground Railroad, which was neither a railroad nor actually underground. It was a loose network of individuals and houses sympathetic to the abolitionist cause. These people would house the escaped slaves and send them on to the next "station," so slaves could gradually make their way north. Tubman's work became even more dangerous after Congress passed the Fugitive Slave Act in 1850. This act required citizens of any state, slave or free, to assist in the capture and return of runaway slaves. Tubman also served for the Union during the Civil War. She worked as a spy behind Confederate lines, Which of these best describes the relationship between Harriet Tubman and the Union Army?​