What was the major cause of african american migration from the rural south to northern cities during world war i?

Ineed answers 5 and 6 on my social studies homework reply to this question i posted

1• political and economic system greatly influenced by the ideas karl marx • factors of production owned by the government • production and distribution of goods controlled by central planners what form of government is described above? a. monarchy b. direct democracy c. communism d. oligarchy

What was one effect of the emancipation proclamation on african americans in the north?