Answer:
The First Great Migration (1910-1940) had Black southerners relocate to northern and midwestern cities including: New York, Chicago, Detroit, and Pittsburgh. When the war effort ramped up in 1917, more able bodied men were sent off to Europe to fight leaving their industrial jobs vacant. The labor supply was further strained with a decline in immigration from Europe and standing bans on peoples of color from other parts of the world. All of this afforded the opportunity for the Black population to be the labor supply in non-agricultural industries.
Step-by-step explanation: