Which of the following was a key cause of world war 2

Answer: The major causes of World War II were numerous. They include the impact of the Treaty of Versailles following WWI, the worldwide economic depression, failure of appeasement, the rise of militarism in Germany and Japan, economic downturn, revenge, hatred, Nazi ideology and Lebensraum, the rise of extremism and the forging of alliances and the failure of the League of Nations.