USA HISTORY

Detailed explanation-1: -With the decline of the Ottoman Empire, Serbian nationalism continued to rise, culminating in the assassination of the Archduke of Austria in 1914 by a Bosnian Serb and officially triggering the start of the Great War.

Detailed explanation-2: -Nationalism was a particularly important cause of World War I due to several key factors. For instance, it caused nations to build up their armies and led to increased militarism. As well, it created extremely high tensions in Europe in the decades before the outbreak of the First World War.

Detailed explanation-3: -The immediate cause of World War I that made the aforementioned items come into play (alliances, imperialism, militarism, nationalism) was the assassination of Archduke Franz Ferdinand of Austria-Hungary. In June 1914, a Serbian-nationalist terrorist group called the Black Hand sent groups to assassinate the Archduke.