Question

allied forces experienced high death rates because
the german ground war was very successful.
they had to protect countries near the balkans
many deaths were soldiers and civilians from their colonies
us forces had no safe places, since they were far from home.

Explanation:

During certain wars, a successful German ground - war could lead to high Allied death rates as they face strong German military opposition. Protecting Balkan - adjacent countries doesn't directly explain high death rates. Deaths from colonies don't explain why Allied forces overall had high death rates. The fact that US forces were far from home doesn't comprehensively account for high Allied death rates. The most likely reason among these for high Allied death rates is a successful German ground - war.

Answer:

the German ground war was very successful.