How did the alliance system in europe most likely contribute to the start of world war i?
a. the countries in the alliances sought protection against enemies by sharing military personnel.
b. the countries in the alliances agreed to work together to gain power through colonization.
c. the countries in the alliances agreed to share economic resources based on open trade markets.
d. the countries in the alliances signed treaties agreeing to defend each other in times of war.

D. The countries in the alliances signed treaties agreeing to defend each other in times of war.

Explanation:

There were two fundamental collisions in Europe preceding WWI: the Triple Alliance (Germany, Austria-Hungary, and Italy) and the restricting Triple Entente (the Soviet Union, Britain, and France). These collisions are what made the war heighten from what ought to have just been provincial clash into a war all through Europe and that's just the beginning.

d. japan's attack on pearl harbor

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