Final answer:
During World War I, Germany allied with their number-one fear, France, while Russia and the Ottoman Empire also sided with Germany. Britain, France, and Russia made up the Allied Powers.
Step-by-step explanation:
During World War I, one country allied with their number-one fear was Germany. Germany's number-one fear was being surrounded by hostile nations, which included France and Russia. When Germany invaded France through neutral Belgium, England honored its treaty to aid France, and the Ottoman Empire and Bulgaria also sided with the Central Powers. On the other side, the Allied Powers comprised of Britain, France, Russia, and eventually the United States.