<P> The war of attrition then focused on another resource: human lives . In the Battle of Verdun in particular, German Chief of Staff Erich Von Falkenhayn hoped to "bleed France white" through repeated attacks on this French city . </P> <P> In the end, the war ended through a combination of attrition (of men and material), advances on the battlefield, arrival of American troops in large numbers, and a breakdown of morale and productivity on the German home - front due to an effective naval blockade of her seaports . </P> <P> As with most technologies, aircraft and their use underwent many improvements during World War I. As the initial war of movement on the Western Front settled into trench warfare, aerial reconnaissance over the front added to the difficulty of mounting surprise attacks against entrenched and concealed defenders . </P> <P> Manned observation balloons floating high above the trenches were used as stationary observation posts, reporting enemy troop positions and directing artillery fire . Balloons commonly had a crew of two, each equipped with parachutes: upon an enemy air attack on the flammable balloon, the crew would jump to safety . At the time, parachutes were too heavy to be used by pilots in aircraft, and smaller versions would not be developed until the end of the war . (In the British case, there arose concerns that they might undermine morale, effectively encouraging cowardice .) Recognized for their value as observer platforms, observation balloons were important targets of enemy aircraft . To defend against air attack, they were heavily protected by large concentrations of antiaircraft guns and patrolled by friendly aircraft . </P>

Was there any specific technology used in world war 1