The territories of Poland was known to have expanded as agreed on the Treaty of Versailles right after the first world war. Germany looses most of its territories at that time and some of it were given to the Polish. Poland acquired these German territories: West Prussia, Posen and Upper Silesia.
A massive topic for this could be oil. You could talk about OPEC and the different types of technologies involved
I’m pretty sure it would be c
D which would be armed conflict with the Southern soldiers
Changes: Constitutional end to slavery and granted citizenship and voting rights.
Continuities: Blacks continued to work on plantation lands doing much the same work as before 1865. They were segregated from whites and often were not given the right to vote.