I choose World War II.
It was not just about armies fighting each other but also concerned the
decimation of an entire race of people.
During WWII, the Germans tried to
wipe out the Jews in Europe and almost succeeded had not the allies arrived and
liberated the camps where the Jews were held. This also led the establishment of international laws to prevent genocide and convict those who perpetuate it.
4) African economies became dependent on the sale of cash crops and raw materials.
D. A slave would count as three-fifths of a
person when counting population for
representation
Lesotho is the country you are looking for :)