Answer:
WWI started when a group set out to kill Archduke Franz Ferdinand, the heir to the Austro-Hungarian Empire, and did. It was a world war because it created a sense of the whole world collapsing. The only reason it was a world war was because of loyalty between countries so the allies had to help the allies, if it wasn't for that we wouldn't have needed to have a world war. However, the partnership between countries is what unites the world, which in some cases is very nessecary.
Explanation:
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