It would be <span>Some nations agreed to disarmament but some did not. Nations which has large armies and weapons usually doesn't agree in disarmament because it will give a strain and more effort are required to disband to follow the disarmament treaty. Also those nations who have an advantage in military power would not agree to lessen its power for the lesser power.</span>
Trench Warfare was a form of military conflict in which opposing sides fought one another from trenches facing one another. WW1 warfare introduced the first large-scale use of chemical weapons as well as bringing in airplanes and tanks for the first time.