Answer:
The Balkan Wars and their aftermath clearly provided the backdrop to accession negotiations with Central and Eastern European countries, brushing aside most.
Explanation:
Their entry into the war boosted the morale of the other allied nations. Morale completely depleted seems how the war was ultimately a stalemate and lives were being lost needlessly. American entry into the war also discouraged the Axis powers, and later after America's entry the Axis powers began to drop deeper into fear. America was the turning point for the war. The Axis powers were winning and if it weren't for America, then the Axis powers would have prevailed and the world would not be the way it is today. (This is what I think about it, it might not be entirely correct.)
From Europeans because the Europeans brought slaves from Africa to sell to America
Trans-Saharan trade requires travel across the Sahara between sub-Saharan Africa and North Africa. While existing from prehistoric times, the peak of trade extended from the 8th century until the early 17th century. ... Cattle were introduced to the Central Sahara (Ahaggar) from 4000 to 3500 BC.