The use of technology during WWI change the face of the battle. Machine funs could wipe out an entire line of people. There was no need to march in line and fire at each other anymore. This led to massive slaughter and rose the number of deaths. Machine guns, tanks, flamethrowers, poison gas, trace bullets, interrupter gear, and other technology was invented. Overall the war could have been much longer if there weren't any of these new technologies.
