Question

Which of these events ultimately led to World War I? Choose three answers.

The assassination of Archduke Franz Ferdinand angered Austria.
Serbia declared war on Austria, which caused Austria’s allies to go to war.
Nationalism increased tensions in the Balkan peninsula.
Russia's mobilization plan called for an invasion of France through Belgium.
Alliances caused a chain of events that pulled each country into war.

Answer 1

Answers:
- The assassination of Archduke Franz Ferdinand angered Austria.
- Nationalism increased tensions in the Balkan peninsula.
- Alliances caused a chain of events that pulled each country into war.

Brief reasons:
- The assassination was the immediate trigger that gave Austria-Hungary a pretext to act against Serbia.
- Balkan nationalism (especially Slavic nationalism and Serbian irredentism) created long‑running regional instability.
- The system of alliances (Triple Entente vs. Triple Alliance) transformed a localized crisis into a general European war.

Why the other two are incorrect:
- Serbia did not declare war on Austria; Austria-Hungary declared war on Serbia.
- The plan to invade France through Belgium was Germany’s Schlieffen Plan, not a Russian mobilization plan.