During the short lived political unity of the Islamic empire, Muslims were ruled by a: O caliph
O Kaaba
O Pope
O patriarch

answer: you could try asking a family member maybe?

explanation:

the addition to geographic boundaries that might have  kept the people of the huang river civilization from traveling to far distance region is that they had learned about the other river valley civilizations but feared contact would bring invasion.

hope this .

plz give me brainliest!