During World War I, the arrival of American troops boosted Allied morale because they refused to join to battle at the Meuse-Argonne.
provided more than one million reinforcements.
taught Allied troops how to build trenches.
forced German troops to evacuate France and Belgium.

the answer wold be b) travel among nations should be regulated by an international organization

the correct answer that would best complete the given statement above would be option b. expanding civil services. diocletian and constantine paved the way for foreign invasion by dividing the empire, creating administrative bureaucracies and reorganizing the military, except for expanding civil services. hope this answer .

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explanation:

frederick william of brandenburg-prussia trained his son, frederick, to be a hardy soldier. but frederick disliked rifle shooting and horseback riding. unlike his father, he was interested in french literature. he enjoyed poetry and music and, like some others of the enlightenment, he scoffed at religion. his father thought him soft, frivolous and unmindful of his duties. and when frederick refused to put his signature on a right to succession, for a few moments his father strangled him.