archduke Franz Ferdinand got assassinated, and all his allies attacked the country where the assassins were from, and then all of those countries allies attacked the allies of the countries attacking their ally, and then there was trench warfare in Europe, first tanks came around, poison gas was used and was very deadly, and in the end Germany got their butt kicked
Mechanized Warfare is the one that allowed for the safe transport of American troops to Europe. Merchanized Warfare ii also known as Armoured warfare or tank warfare which is the use of armoured fighting vehicles in mordern warfare. It is used to transport safely the troops of America to Europe.