World War I was one of the deadliest conflict in human history because A) of the massive loss of life do you to the automatic weapons in the Pacific in the holocaust in Europe
B) New military technology like airplanes machine guns tanks and poisonous guys made combat deadlier than ever before
C) improved transportation and shipping methods made getting troops and supplies from one place to another easier than ever before
D) improved medical technology and message to reduce the efforts of disease and improved survival rates for soldiers wounded in combat