(1) A series of wars in the region and finally the First World War in 1914
(2) Opposition to imperial domination in the colonies
(3) The idea that societies should be organised into nation states
(4) All the above

(1) Armies being trained by revolutionaries
(2) All revolutionaries trained to overthrow monarchy
(3) Secret societies being formed in many European states to train revolutionaries and spread their ideas
(4) All the above

(1) Major European powers manipulated nationalist sentiments of the people to further their own imperialistic designs
(2) Nationalist groups had become intolerant of each other
(3) Nationalism had become a narrow creed with limited ends
(4) All the above

(1) The Balkan states were very jealous of each other
(2) Each state wanted to gain more territory at the expense of others
(3) The Balkans were also the scene of big power rivalry
(4) The Balkans were not under the control of Ottoman Empire