Why did the invasion of poland have a significant effect on world war ii?

It caused both Greath Britain and France to declare war on Germany (Ap3x)

Explanation:

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.

it was on the rise and doing very well and would continue to do well until the great depression from 1929-1939