Why was there racial unrest in northern cities after world war i?
a. african-american baseball players were being allowed to play on previously all-white teams.
b. the migration of african americans and returning african-american veterans had created greater competition for jobs and housing.
c. the arrival of large numbers of immigrants from eastern europe caused tensions with african americans.
d. african americans had been given the right to vote for the first time.?

b. The migration of African Americans and returning African-American veterans had created greater competition for jobs and housing.

Explanation:

The years after WWI saw many people in the country changing residence. Many soldiers and veterans came back home. Many immigrants also arrived to the United States. However, the main movement of people consisted of African Americans who left the rural areas of the South to travel to cities in the North. This was both a consequence of the segregation that existed in the South as well as the better economy of the North. This migration led to increased competition and therefore, racial unrest.

the correct answer option is: weapons.

explanation:

tensions rose as the two opposing superpowers competed for 'weapons'.

referring to the cold war (1945-1991), the two superpowers, usa and ussr, experienced a phase of struggle and conflict with each other. these two superpowers considered each other as a threat to their survival and thus opted for policies to strengthen their positions.

the two superpowers never went to war with each other directly but competed for weapons to preserve their positions.