Final answer:
The Allied Powers at the outbreak of World War I were France, Great Britain, and Russia.
Step-by-step explanation:
The countries that belonged to the Allied Powers at the outbreak of World War I were France, Great Britain, and Russia. These countries, along with other nations that joined later, formed the alliance known as the Allies or Triple Entente. Their main opponents were the Central Powers, which included Germany, Austria-Hungary, and Italy.
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