Final answer:
The Allied armies showed signs of exhaustion through strategic errors, morale breakdown, logistical struggles, and dependence on new U.S. support. The failure of the French to employ effective tank strategies and the depletion of German supplies emphasized the Allies' fatigue, which was only relieved by the influx of American resources and troops that ultimately shifted the balance and led to the armistice ending World War I.
Step-by-step explanation:
The signs that the Allied armies were exhausted include strategic missteps, morale collapse, logistical challenges, and the heavy reliance on new American troops and resources. One of the critical indications of exhaustion was the failure of the French to properly utilize armored divisions, instead scattering tanks among infantry, lacking an understanding of modern tank warfare tactics. Additionally, the Allied Power's morale declined sharply during the battles, particularly as the German and French forces struggled with coordination, contributing heavily to the eventual collapse of their offensive capabilities.
By the time of the Meuse-Argonne offensive, German forces had overextended and depleted their supplies, which left the military command recognizing the impossibility of victory and the necessity of an armistice. The combined effect of German propaganda, concealing the dire state of the German military, led to shock and disbelief among German civilians regarding the surrender, with many buying into the narrative of being 'stabbed in the back' by their leaders. In reality, it was the profound exhaustion and depletion of German forces that made surrender the only viable option to prevent further suffering.
In contrast, the arrival of over one million U.S. troops boosted the exhausted Allied forces and turned the tide against Germany. The final push into German territory saw Allied advances facilitated by a combination of infantry, aircraft, tanks, and artillery largely provided by the U.S. This fresh influx of manpower and material was pivotal in breaking the German lines and ultimately leading to an armistice and the end of the war.