Final answer:
The Allied Powers in World War I initially included France, Britain, and Russia, and later expanded to include countries such as Italy, Japan, Belgium, and the United States.
Step-by-step explanation:
The countries that comprised the Allied Powers in World War I, also known as the Triple Entente, were originally France, Britain, and Russia. This alliance expanded to include additional nations such as Italy, Japan, Belgium, and later the United States. The Triple Entente faced the Central Powers, which included Germany, Austria-Hungary, the Ottoman Empire, and initially Italy until it switched sides to join the Entente in 1915.
Two important alliances before and during the early stages of the war were the Triple Entente and the Quadruple Alliance. The correct answers to the related questions are that the Triple Entente consisted of France, Britain, and Russia, and the four powers of the Quadruple Alliance were Britain, Prussia, Russia, and Austria. However, the context of the student's question specifically pertains to World War I, where the term 'Allies' primarily refers to the countries aligned against the Central Powers.