In a minimum of 5 sentences, what are the MAIN causes of World War I? What was the spark that officially started the fighting?

The main cause was alliance, imperialism, militarism and nationalism (AIMN) and the assassination of Archduke Ferdinand of Austria.

The spark that set off World War I came on June 28, 1914, when a young Serbian patriot shot and killed Archduke Franz Ferdinand, the heir to the Austro-Hungarian Empire (Austria), in the city of Sarajevo. The assassin was a supporter of the Kingdom of Serbia, and within a month the Austrian army invaded Serbia. As a result of the military alliances that had formed throughout Europe, the entire continent was soon engulfed in war. Because European nations had numerous colonies around the world, the war soon became a global conflict. OLEASE MARK ME Brainiest :) LOVE FROM USA