It helped because it enabled other fronts to open up because the American Offensive in the area ended with a victory, which meant that they could move to other areas and bother Germans there. They didn't' do this however because the fighting ended since the Germans became aware of their losses and signed an armistice.
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The person who perfected the steam engine is the very known inventor and early-day scientist James Watt. His work on the steam engine made it widely used and one of the most profitable and turn-overable areas of the industry during those times.
Civil wars. Probably the most important single cause of Byzantium's collapse was its recurrent debilitating civil wars. Three of the worst periods of civil war and internal infighting took place during Byzantium's decline.