Final answer:
The MAIN causes of World War I included Militarism, where nations amped up their militaries; Alliances, which created a domino effect when war broke out; Imperialism, the competition for colonies and resources; and Nationalism, strong identification with one's own nation leading to international conflicts.
Step-by-step explanation:
The four main causes of World War I, summarized by the acronym MAIN, include Militarism, Alliances, Imperialism, and Nationalism.
Militarism
Militarism involves nations building up large militaries in preparation for war. Prior to World War I, European countries such as Germany and Britain were racing to outpace each other with larger navies and armies. This arms race created a tense environment where any conflict had the potential to turn into a full-scale war due to the militarized state of Europe.
Alliances
Alliances were agreements between countries to provide military support if one was attacked. Complex networks of alliances, including the Triple Entente and the Triple Alliance, meant that a conflict involving one power could rapidly draw in others, creating a chain reaction that led to war. The assassination of Archduke Franz Ferdinand triggered these alliances, resulting in a widespread conflict.
Imperialism
Imperialism is the expansion of a country's influence through diplomacy or military force. European powers were competing for colonies and resources worldwide, heightening tensions. The division of Africa at the Berlin Conference in 1885 and other imperialist actions created rivalries that contributed to the outbreak of the war.
Nationalism
Nationalism is a strong identification with one's own nation and culture, often at the expense of others. Intense nationalistic feelings in countries like Serbia and Austria-Hungary set the stage for conflict, as different groups sought self-determination and the advancement of their own nation's power and interests.