<P> In the late 1920s, Germany helped Soviet industry begin to modernize, and to assist in the establishment of tank production facilities at the Leningrad Bolshevik Factory and the Kharkov Locomotive Factory . This cooperation would break down when Hitler rose to power in 1933 . The failure of the World Disarmament Conference marked the beginnings of the arms race leading to war . </P> <P> In France the lesson of World War I was translated into the Maginot Line which was supposed to hold a line at the border with Germany . The Maginot Line did achieve its political objective of ensuring that any German invasion had to go through Belgium ensuring that France would have Britain as a military ally . France and Russia had more, and much better, tanks than Germany as of the outbreak of their hostilities in 1940 . As in World War I, the French generals expected that armour would mostly serve to help infantry break the static trench lines and storm machine gun nests . They thus spread the armour among their infantry divisions, ignoring the new German doctrine of blitzkrieg based on the fast movement using concentrated armour attacks, against which there was no effective defense but mobile anti-tank guns - infantry Antitank rifles not being effective against medium and heavy tanks . </P> <P> Air power was a major concern of Germany and Britain between the wars . Trade in aircraft engines continued, with Britain selling hundreds of its best to German firms - which used them in a first generation of aircraft, and then improved on them much for use in German aircraft . These new inventions lead the way to major success for the Germans in World War II . Germany had always been and has continued to be in the forefront of internal combustion engine development . Göttingen was the world center of aerodynamics and fluid dynamics in general, at least up to the time when the highly dogmatic Nazi party came to power . This contributed to the German development of jet aircraft and of submarines with improved under - water performance . </P> <P> Induced nuclear fission was discovered in Germany in 1939 by Otto Hahn (and expatriate Jews in Sweden), but many of the scientists needed to develop nuclear power had already been lost, due to anti-Jewish and anti-intellectual policies . </P>

Which of the following were developed during world war ii