Answer:
Jim Crow laws - Cause
Jim Crow laws were laws in the Southern States that disenfranchised African Americans, made segregation legal, gave support to hate organizations like the KKK, and reduced their economic opportunities. Jim Crow Laws were one of the main motivations for African Americans to migrate to the Northeast and the Midwest.
More segregated neighborhoods in the North - Effect
Most African Americans emigrated to low-income neighborhoods of urban areas in the Northern states. As soon as they began to move in, most white people left, as some government policies like redlining also promoted this increased segregation.
Harlem Renaissance - Effect
The Harlem Renaissance was an African American cultural movement that emerged in the Harlem neighborhood of Manhattan during the first decades of the XX century. It was caused by the Great Migration due to the large number of black people who moved there during this period.
Violence toward African Americans - Cause
Violence toward African Americans in the South was common during and after the Reconstruction Era. Lynchings and hangings were common, and supported by the authorities. This was one of the main motivations for African Americans to migrate to the North.