(A) Prevented civilian casualties
(B) ** increased casualties
(C) ended the war more quickly
EXPLANATIONS BELOW
Concept note-1: -Technological developments in engineering, metallurgy, chemistry, and optics had produced weapons deadlier than anything known before. The power of defensive weapons made winning the war on the western front all but impossible for either side.
Concept note-2: -World War I popularized the use of the machine gun-capable of bringing down row after row of soldiers from a distance on the battlefield. This weapon, along with barbed wire and mines, made movement across open land both difficult and dangerous. Thus trench warfare was born.
Concept note-3: -With no need to re-aim the gun between shots, the rate of fire was greatly increased. Shells were also more effective than ever before. New propellants increased their range, and they were filled with recently developed high explosive, or with multiple shrapnel balls-deadly to troops in the open.
Concept note-4: -The machine gun came to represent the use of technology applied to weaponry. The power it gave to a single man made the offensive doctrine of the European powers obsolete, forcing the armies on the Western Front into trenches. All of the combatants were left with the option to dig in or be annihilated.