Answer:
"Innovations in machine guns, grenades, and artillery, along with essentially new weapons such as submarines, poison gas, warplanes and tanks in WWI. In WWII they made the the Bazooka, ATOMIC BOMB, M101 Howitzer, Radio Proximity Fuze, the Sherman tank, Poison gas, semiauto and automatic rifles, accurate bolt-action rifles, and the flame thrower. These all were either new, or more developed when war broke out. Also new were airplanes, that introduced the art of dog fighting and bombing enemies."
Step-by-step explanation:
(Found this online.)