How many nations were in world war 1

over 30

Explanation:

Over 30 nations declared war between 1914 and 1918. The majority joined on the side of the Allies, including Serbia, Russia, France, Britain, Italy and the United States. They were opposed by Germany, Austria-Hungary, Bulgaria and the Ottoman Empire, who together formed the Central Powers.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).