Answer:
M - countries were advancing their weapon technology and wanted to test out their weapons as well as prevent others from attacking them because they were scared to be attacked.
A - when a country enters war, the others have to as well, causing a small battle to escalate into a war.
I - counties wanted to conquer other countries which caused tension between them.
N - countries were prideful in their own and they wanted other countries to see how great they were so they spread to spread their power.