Numerous countries rebelled against the Ottomans to establish independent states: Serbia, Greece, Bulgaria, and Albania.
The majority of the Roman Empire supported him because anyone who spoke out against him died.
Russia supported Serbia first, then when Germany entered the war (on the side of Austria-Hungary--the Central Powers), France and Britain joined in as well (on the side of Serbia--The Allies). Bulgaria joined in later (Central Powers), as did Italy (Allies). As it became truly a world war, Japan and the United States joined (part of the Allies), and so did the Ottoman Empire (Central Powers), and several other countries such as Portugal, Romania, etc. on the Allied side.
Serbia become de facto independent from Ottoman empire in 1804. and 1807. And de jure in 1830.
Only some provinces of Serbia and Romania.
When Serbia rejected the Hapsburgh ultimatum, Russia supported Serbia, Germany backed the Austro-Hungarians, who invaded Serbia bringing the triple alliance, (Russia England France) into the First World War. The Ottoman Empire backed Germany and Austro-Hungarians to create the Axis. Italy backed the triple alliance to create the Allies, which defeated the Axis, in 1918. Canada, Australia, New England and other Commonwealth Nations supported England, as they did in WW2.
Serbia because they wanted to be an independent country, however austria-Hungary wanted to rule them to make a larger empire and it was franz ferdinands idea
Yes, it was. It was an empire until Second World War
I don't know that it was State sponsored as such: Gavril Prinzip was a Serbian.
to fight for them
Because serbia didn't want to agree to everything Austria Hungary wanted they invaded serbia which would force Serbia to fight back.
Enemies in the "Great War " were : - Austro Hungarian empire - Germany - Ottoman empire - Bulgaria