Answer:
Britain, France, Russia, Germany, Italy, Austria-Hungary and the Ottoman Empire.
Step-by-step explanation:
After the assassination of the Austro-Hungarian heir, Archduke Franz Ferdinand in Sarajevo led to the series of the diplomatic and military rises which we know as the July Crises. The July Crisis started the first World War in 1914 in Europe. The war extended and formed two sides, the Central Powers and Allies. The Central Powers formed after signing a treaty of Triple Alliance which included nations like Germany, Austria- Hungary and Italy. The Ottoman empire joined later in the war with standing in favour of the Central Powers. The Allied Group created after Triple Entente which included Britain, France, and Russia.