Answer:
Alliances are an agreement when two or more parties to join and make each other stronger.
In WW1 there were a couple of allies. One side of allies were Britain, France, Russia, Italy and the United states. They were fighting against the "Central Powers" were Germany, Austria- Hungary, Bulgaria, and the Ottoman empire.
WW1 really triggered when the the Heir presumptive of Austria-Hungary was shot to death by a Bosnian man, then a chain pf events happened and Austria-Hungary blamed it on the Serbian Government.
Step-by-step explanation:
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Hope this helps!