Question

During the Civil War, African American military units

Answer 1

During the Civil War, African American military units were mistreated in the Northern units. They were not able to rise higher ranks than a coporal (?)
and were mistreated by some of the white generals, who thought that African Americans "couldn't fight the same as a white can". However, they were valuable soldiers, and on more than one occasion help win a battle for the Union. Hope this helps :D

Answer 2

Correct answer:  Were usually led by white officers.

Details:

According to a National Archives article on "Black Soldiers in the U.S. Military during the Civil War" -

• In addition to the perils of war faced by all Civil War soldiers, black soldiers faced additional problems stemming from racial prejudice. Racial discrimination was prevalent even in the North, and discriminatory practices permeated the U.S. military. Segregated units were formed with black enlisted men and typically commanded by white officers.

At the start of the war, black soldiers were also paid less than white soldiers.  In 1864, however, the US Congress corrected the problem of unequal pay, and made the measure they passed retroactive, so that black soldiers would receive retroactive wages to compensate for that previous inequality.