Certain portions of the land either do not meet our needs for survival or they are uninhabitable due to climate, altitude, and/or the air quality in those regions.
Barbarian groups were able to weaken the Byzantine Empire<span> because the empire itself had several unprotected areas for warring </span>groups<span> to invade.
Hope this helps!
-Sammy</span>
They both were economically strong but had weak military forces. I hope this helps!
