America geography questions

how far did the peirod 1915- 41 sees a major change in the geographical pattern of black americans? (20)

1) the extent of chnage brought about by the Great migration- exceptional change 7 million moved. caused by WWI defense migartion increase employment oppertunities 

2) compare to Pre 1915- slow drift North

3) compare Great migration changes afer 1940s- 1970s moving back 53% moved back…