Claim: World War I involved one group of countries fighting another.
Evidence: The war drew in all the world 's economic great powers , assembled in two opposing alliances : the Allies -LRB- based on the Triple Entente of the Russian Empire , the French Third Republic , and the United Kingdom of Great Britain and Ireland -RRB- versus the Central Powers of Germany and Austria-Hungary.
The Allies of World War I , or Entente Powers , were the countries that opposed the Central Powers in the First World War.
The Central Powers -LRB- Mittelmächte Központi hatalmak İttifak Devletleri or Bağlaşma Devletleri Централни сили Tsentralni sili -RRB- , consisting of Germany , , the Ottoman Empire and Bulgaria -- hence also known as the Quadruple Alliance -LRB- Vierbund -RRB- -- was one of the two main factions during World War I -LRB- 1914 -- 18 -RRB-.