Poison gas was introduced by Germany and both sides of alliance used poison gas. Poison gas caused blindness, blisters and caused death by choking. Therefore many soldiers used mask to prevent themselves from breathing the deadly gas.
The machine gun was a machine that fires automatically rapidly. It was a bug weapon that cause most of the causalities. Men who went "over the top" were killed instally.
Tanks were a armored combat vehicles that had chains as wheels. The tank was mobile and not liked by the people in trenches.
As well as the poison gas Germany introduced submarines as a effective worship. The submarines were used as weapons against ships called the torpedo.
"Machine Guns." Machine Guns. N.p., n.d. Web. 13 Jan. 2015.
"Tanks and World War One." Tanks and World War One. History Learning, n.d. Web. 12 Jan. 2015.