What effect did the eastern front have on World War I? Select all that apply.

A. The eastern front weakened Austro-Hungarian forces, making them less effective on the western front

B. The Central powers surrendered to the Allied powers due to their losses to Russia on the eastern
front

C. The eastern front ended within one year and did not have an important effect on the outcome of the
war

D. The heavy Russian losses, combined with food and fuel shortages, led to the abdication of Czar
Nicholas II