The world plunged into World War II in 1939 for many reasons. The reasons were Japan's invasion of Manchuria, Mussolini's attack on Ethiopia, and Hitler's defiance of the Treaty of Versailles. Pacification was one of the most important things that led to World War II. Appeasement was giving in to an aggressor to keep the peace. It basically postponed the outbreak of the war, but it didn't stop the war from happening. The most effective response to aggression at this time was collective security because it used appeasement to bring countries together without benefiting them. One of the reasons the world plunged into World War II in 1939 was Japan's invasion of Manchuria. it was an area rich in iron and coal. Japan had gone to other places to invade them and steal their raw materials. According to outside information, they killed 100,000 innocent Chinese in Manchuria. The world was furious with the Japanese. Therefore the United States had chosen to impose an oil embargo on Japan and not sell them oil in Hawaii or any other port until they stopped their actions. The Japanese attack on Manchuria was the first direct challenge to the League of Nations. When this happened many members of the league protested strongly. Japan simply ignored these protests and responded by leaving the League. Another reason for the Second World War was Mussolini's attack on Ethiopia. Ethiopia was one of the three independent nations of Africa. According to external information, Mussolini dreamed of building a colonial empire in Africa like those of the English and France. Therefore, to gain Ethiopia, Mussolini ordered a massive invasion of Ethiopia in October 1935. Ethiopia had no chance to defend itself from this attack. .This is a similar process that occurred when… halfway through the document… he walked away from this meeting due to appeasement. Europe was happy because it avoided war. This, however, did not help the Czechs at all. For some reason, Chamberlain was in favor of appeasement. According to Document 5, he thinks appeasement is the best way because he believes war is a "scary thing." He thinks that pacification will benefit Europe. World War II happened for many reasons, which most likely no one could have stopped. sooner or later it will happen. By using appeasement in the beginning, we were simply giving Hitler exactly what he wanted, which was not good at all. But with Collective Security, Europe has finally done what needed to be done to regain the power it had just relinquished. it is the most effective response to aggression because it does not allow the aggressor to get what he wants and to gain too much power over everyone.