How Could One Act of Terror Cause a World War?

'How could one act of terror cause a world war? Explain the causes behind World War I and what might have been done to prevent it
1914, World War One began, the most horrific war the human race had ever seen, lasting for 4 years and precisely three months. Estimates of just over 30 million people were killed. Those who lived through this war referred to it as the 'Great War', we as a country lost just fewer than sixty two thousand lives. But what lit the fuse, what event sparked the domino styled war which inturn took so many innocent lives? And more importantly, who was responsible?
This war, was a war in which country after country was dragged into deadly disputes all because of a 'peace-keeping' strategy called the alliance system; in which was set up to protect countries from starting a war. Basically the alliance system was set up to balance major countries and stop them for fighting based on a 'we have exactly equal power as you so if you attack us we'll attack you back just as bad' theory.…