They contributed to World War 1 through the assassination of Archduke Franz Ferdinand. The Black Hand was part of a Pan-Slavist movement in which they wanted to unite territories of South Slave that had been annexed by Austria-Hungry. Hopefully this helps.
By being in the north and wanting the south to rid of slaves, and to make them join the north. but the south only had huge amounts of farm land, and no way to sow, till, or harvest all that land with out a few hundred slave workers. the north seen that as unnescessary to do. the north also laid out laws that the south didnt agree with leading to the southern states declaring independancy against the north witch lead to war.
Hello!
I cannot answer A) as that requires your personal opinion, but I shall answer B):
B) Answer: After WW1, Germany was left with a reduced territory, a huge sum to give her former opponents as war reparation, a huge debt and a hurt pride. All of this let people confused, angry and depressed.
*Plaigarism Free
I hope this helped you! c: