Which of the following contributed most to the success of German blitzkrieg tactics? The massive improvement in airplane technology. The resumption of unrestricted submarine warfare.

The target's access to underground tunnels and shelters.

The use of a military draft to secure large numbers of infantrymen.

Which statement best describes a significant cause of world war ii? o a. the economic boom that followed world war i allowed countries to build up huge militaries. o b. the treaty of versailles, which ended world war i, left lasting resentments in many countries. o c. the rise of imperial states in asia caused european powers to unite for their common defense. o d. the league of nations encouraged european states to form secret military alliances.