Question

Which best explains why barbarian groups were able to weaken the Byzantine Empire?

The empire directed its spending on trade, not building up the army.
The empire's territory was extremely small and open for invasion.
The empire's armed forces had little combat experience.
The empire had several unprotected areas for warring groups to invade.

Answer 1

I would say the last one

Answer 2

I agree,because Barbarian groups were able to weaken the Byzantine Empire because the empire itself had several unprotected areas for warring groups to invade.