Which military blocs fought among themselves in the First World War?

In the First World War, two military-political blocs clashed: the Entente and the Triple Alliance. They formed at different times, but the enmity between them did not subside. In 1882, Germany, Austria-Hungary and Italy united in order to then fight with England and France for colonies and spheres of influence. In 1907, in response to this aggression, the Entente was created, initially consisting of Russia, England, and France. Later, the Entente was joined by other states that played a secondary role in the war.