CLEP Western Civ II

Answer: C - The invention of the machine gun gave rise to trench warfare. The machine gun emerged at the end of the American Civil War, and the Siege of Petersburg (Virginia) used trench warfare tactics, since the only defense against the spray of bullets machine guns produced was to be in the ground. Because this style of warfare made battles virtually impossible to win, World War I saw some of the most prolonged and bloody battles in military history. The invention of the airplane and development of tanks, which were both in use by the end of World War I, rendered trench warfare ineffective.