What were the four trends that pushed europe toward war in the late 1800s and early 1900s?

The four trends that pushed Europe toward war in the late 1800s and early 1900s were:

1 - The alliance system

2 - Militarism: which means that either the government or the people or both desired to keep a very strong military capability. This military capability was then used aggressively to spread the country's interest and promote them.

3 - Nationalism: which means that there was a group of different systems (political, economic and social) working on promoting interests of a particular nation in order to gain self-governance, or full sovereignty, over the group's homeland.

4 - Imperialism: which means that the country actually expanded its power by the acquisition of territories