Why did rome need barbarian warriors?

Apex plz i’m almost done if i get this all right

Which of the following scenarios illustrates the cultural impact of expanded regional trade for postclassical civilizations? o a. the byzantine empire rises in place of the roman empire. o b. an islamic scholar attends a university in his hometown. o c. internal disputes weaken a large african empire. o d. an arabian sultan wears a robe made from chinese silk.

What was america's response to the holocaust before the war? what could the us have done differently?