Answer :
There were three notable factors that led to world war I. These were the Sarajevo Assassination, the escalation of violence in Bosnia and Herzegovina and the July Crisis. The Sarajevo assassination was when the Austrian archduke Franz Ferdinand and his wife, Sophie, were assassinated in their convoy. The escalation of violence has said that it was incited by the Austrians who escalated already tense relations between Bosnian and Croat Muslims and ethnic Serbs, with the former attacking the latter. The July Crisis were many big European powers starting to deploy and mobilize before the war, because they did not like the assassination of the archduke and wanted to end Serbian and Austrian rule over the Balkan powers. Germany felt particularly threatened by the Soviet Union who had already started to mobilize.