Poisonous gas was used to kill enemies by filling the air with poison. The gas fills up in the enemy lungs and it suffocates them. Poisonous gas changed warfare because it required no physical contact between the two opposing countries and also did not require one side to be present at the time of war.
Machine guns are automatic guns that are far more advanced than the average rifle and were used to efficiently shoot almost endless rounds of bullets at a time without reloading. Machine guns revolutionized warfare because they made warfare more efficient by improving the average rifle.
Tanks were used to efficiently move toward enemy lines during warfare, while still having the security of a trench, safebox, etc. The tanks revolutionized warfare by creating a moving vehicle that also functions as a place for you to hide in, while also being able to attack the enemy.
Submarines were used to efficiently travel underwater and be undetected. Submarines revolutionized modern warfare because it allowed you to come within yards of your enemies without them detecting you.
- "Firstworldwar.com." First World War.com. Web 15. Jan. 2015.
- II, John, "tank, Military." The Columbia Encyclopedia, 6th Ed.. 2014, "tank." The Oxford Pocket Dictionary of Current English. Encyclopedia.com. HighBeam Research, 1 Jan. 2000. Web. 15 Jan. 2015.