They have been using rifles since before the world war. Its at the top of the list because it can only hold 10 bullets.
barbed wire became a deadly defensive weapon during the Great War. It caught on equipment and clothing and slowed attackers, who were often prime targets for snipers as they desperately tried to disentangle themselves.
The machine gun was refined in the world war to make it more deadly and lighter, they could fire 400 rounds minute
The majority of casualties on the battlefields of World War I were inflicted by artillery shelling. Artillery barrages to “soften up” enemy lines before an infantry assault could last for weeks. Field guns such as the British Howitzer Mark 1 could fire two rounds of 290 lb shells a minute,
Chlorine gas was first used by the Germans at the Second Battle of Ypres killing hundreds of French troops. Poison gas could be delivered with greater precision by chemical shells and mortars, and there were an estimated one million gas casualties on all sides throughout the war.
When the war started, most of the planes had a few unarmed, wood-and-canvas aircraft, which they intended to use as aerial scouts. By 1914, though, pilots were dropping grenades on enemy troops as they flew over them, or carrying pistols to take pot shots at other aircraft. Air warfare took a leap forward the following year with the adoption of the machine gun mounted on a plane.
The tank was specifically developed to break the trench warfare stalemate – their armor would be impervious to machine gun fire, and their tracks would be able to cross trenches and barbed wire entanglements. But although the tanks at the Somme weakened German morale, they were slow and beset by mechanical problems.
the German military in 1914, and began bombing missions over Britain at the start of the following year. There were just 20 of these airships in operation at any one time, but as they flew above the reach of British aircraft they bombed almost with impunity
Germans used submarines to kill the British navy, The submarines are the main reason why the U.S. joined in when Germany killed 100 people.
the U-boats were to surface before attacking merchant ships with their guns. At the last minute, the Q-ship would open fire on the surfaced submarine, destroying it.