I think the most important reason why Germany lost the war is because the British Navy created a naval blockade. Their aim was to stop Germany using neutral Scandinavian and Dutch ports to break the blockade. To do this Britain had to stop and search any boat they suspected to be trading with the Germans. They confiscated any goods thought to be for use of the enemy. They successfully managed to prevent food supplies, fertiliser and fuel reaching Germany.
The consequences of this blockade proved to be devastatingly effective against the Germans. The shortages of food and fuel caused riots and mutinies in Germany. Also the troops fighting in the war were quickly running out of food.
Another reason why Germany lost the war was because the USA entered the war. Although to start off with the USA suffered great casualties (because their troops were relatively inexperienced compared to the German army) they managed to inspire the French and British troops. One French soldier even said that when they arrived it was as if “new life” had come “to bring a fresh, surging vigour to the body of France, bled almost to death”.
In Summer 1918 the American troops started to make a big difference. Germany had just advanced to within 38 miles of Paris, they had thrown all they had at the Allies but British and French soldiers backed up with over 2 million fresh American troops, launched a series of counter attacks that forced the Germans back. By the end of August the Germans had lost all the ground they had made and were still retreating. The Americans were so effective because they were fresh troops and boosted the Allies exhausted forces. They did were at reinforcing the Allies.
The breakthrough in tank technology proved to be a valuable asset to the British and French. In November 1917, at Cambrai in France 378 Allied tanks advanced 5.5 miles in one day. This is the same distance their troops advanced in a terrible three month massacre that killed over 400,000 people at Passchendaele in Belgium. At this battle the tank secured its reputation as an invaluable offensive weapon in the First World War.
Finally, Germany had to fight the war on two fronts- on the east against Russia and on the west against Britain and France. This caused great strain on the German economy and by the end of the war they found it very hard to distribute food to all their troops. As Germany was fighting a war on two fronts this greatly helped the Allies as Germany could not have all of its troops in one place. It made the number of troops they had to fight on each front less.
