Answer:
In my opinion the most important cause for the World War I was the imperialism view of several countries at that time.
Explanation:
Imperialism, Imperialism is the sought of conquering different territories and make them live under the rule of an Imperialist country. This view is also a long-term cause and depicts how in a given point a country's eagerness for domain other nations will result in a military conflict.
In World War I the Germans have a strong Imperialism view of the world as well as French, England, and Russians.