The WWI tank was the first completely armored vehicle. It was a British invention. It had tracks so the tank could go over nearly all terrain. The tank helped mobilize the war out of trench warfare with a way to cross no mans land. Tanks gave the army an advantage because they were hard to take down and could lead an Army into enemy lines.
The Machine Gun was a gun that could shoot thousands of rounds a minute. This innovation could take out entire enemy troops. This innovation helped during the World War because army's could gain ground by taking out so many enemies or defend themselves better with the automatic machine gun.
The submarine was invented by the Germans. A submarine could submerge completely under water and shoot torpedoes. This gave the Germans an advantage in the water because they could be almost undetectable. The submarines helped give the advantage need to win battles.
The poison gas used in WW1 by both sides, the central powers and allies. The Germans invented poison gas and it had advantages. Some include that the poison gas could be used to take out enemy troops without getting close to them. Soldiers used gasmasks to protect from the poison. Some affects of the gas were death, blistering and severe choking.