Final answer:
The Allies in WWII were the United States, the Soviet Union, and Britain, who joined forces against the Axis powers and ultimately achieved victory in 1945.
Step-by-step explanation:
The primary Allied powers during World War II were the United States, the Soviet Union, and Britain. These nations formed a coalition to fight against the Axis powers, which included Germany, Japan, and Italy. The Allied forces worked cooperatively on multiple fronts throughout the war, engaging in significant battles such as the Battles of Stalingrad and Midway, which are regarded as turning points in the conflict.
The Arsenal of Democracy, an initiative by the US, supplied vital support to the Allies, while technological advancements also played a crucial role in the war effort. Despite suffering heavy losses, the Allies eventually triumphed, bringing an end to World War II in 1945.