Final answer:
Nationalism, imperialism, militarism, and alliance system caused World War 1
Step-by-step explanation:
The main causes of World War 1 were nationalism, imperialism, militarism, and the complex system of alliances between European powers. Nationalism fueled tensions between countries as they sought to assert their power and dominance. Imperialism led to competition between nations for colonies and resources. Militarism increased the size and strength of the military in preparation for conflict.
Furthermore, the complex alliance system, which divided European powers into two main groups, created a situation where a conflict between two countries could easily escalate into a full-scale war involving multiple nations. The assassination of Archduke Franz Ferdinand of Austria-Hungary by a Serbian nationalist in 1914 served as the trigger that ignited the war.
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