Explain what it means to have a supportive environment for the rise of a social movement.

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explanation:

although world war i began in 1914, the united states did not join the war until 1917. the additional firepower, resources, and soldiers of the u.s. to tip the balance of the war in favor of the allies. remaining neutral. when war broke out in 1914, the united states had a policy of neutrality.

a. poison gas was sprayed over battlefields by airplanes to weaken enemy positions before major attacks.