Answer:
The major causes of World War I are generally considered to be the following:
Militarism: The aggressive buildup of military forces and weapons by European powers, particularly Germany, contributed to a sense of tension and competition between nations.
Alliances: The system of military alliances between European nations meant that an attack on one nation could quickly involve others, creating a domino effect of war declarations.
Imperialism: The competition for colonies and resources around the world, particularly in Africa and Asia, heightened tensions and rivalries between nations.
Nationalism: Strong feelings of national pride and identity led to a desire for expansion and dominance among nations, further fueling tensions and competition.
The Assassination of Archduke Franz Ferdinand: The assassination of the Archduke of Austria-Hungary, Franz Ferdinand, by a Serbian nationalist was the immediate trigger for the outbreak of World War I.
The discovery of penicillin, on the other hand, was a medical breakthrough that occurred after World War I and had no direct impact on the causes of the war.