Which domestic shift most affected the demographic makeup of northern us cities in the early 1900s?
a. migration of african americans from southern farms to northern factories
b. influx of illegal immigrants from mexico and central america
c. discovery of large coal deposits in some midwestern states
d. us acquisition of puerto rico and the philippines after the spanish-american war
e. us victory over mexico in the mexican-american war

The correct answer is A. Migration of African Americans from southern farms to northern factories.

This movement is known in American history as the Great Migration. Besides the economic opportunities available in the north, African Americans also moved to the north for a greater sense of freedom. At this time, racial tensions in the south were very high. The existence of Jim Crow laws and the constant presence of the Ku Klux Klan made southern states undesirable for African American citizens.