Final answer:
The causes of World War I were complex and multifaceted, encompassing long-term factors such as Militarism, Alliances, Imperialism, and Nationalism, as well as the immediate trigger of the assassination of Archduke Franz Ferdinand.
Step-by-step explanation:
The causes of World War I were complex and multifaceted. The long-term causes include Militarism, Alliances, Imperialism, and Nationalism (MAIN). These factors contributed to a tense and competitive atmosphere among European powers.
Additionally, the immediate cause of the war was the assassination of Archduke Franz Ferdinand, which triggered a chain of events leading to the outbreak of war.