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Answer:
Nationalism and alliance caused division between countries leading to disputes.
This was because when alliances were made it caused countries to team up against eachother for protection from attacks.Alliances caused disputes as it was seen as taking sides causing issues between nations. Also nationalism contributed to the outbreak of war too as it caused hatred as some nations and groups beloved they were superior or better than others causing segregation.
Ultimately , both nationalism and alliance systems played a huge role in provoking the outbreak of the First World War as it caused conflict between countries causing wyhe war to soon become inevitable.