Based on what you have learned about the religion, economy, and physical geography of medieval europe, why do you think the muslims were not able to conquer most of that continent?

the birth of Arabian civilization can be dated to 7th century A.D. Then Islam was spreading westwards to northern Africa...from  Egypt to Maroccos. From Maroccos Muslims spread to Iberian peninsula. But they were not able to move more northwards beyond Pyrenees. Christian states were stable, well-organized and were able to organize their armies and protect themselves.

Explanation: they were not able to move beyond Pyrenees because already in the north of Iberian peninsula there were well-organized Christian kingdom. They were small but they constituted a barrier. The only significan Arabian invasion to Europe consitutes "battle of Poitiers" (sometimes called "battle of Tours) in 732 A.D. There Franks led by Charles Martel were victorious and Arabians had to retreat behind Pyrenees. Later on Arabians were expulsed from Iberian peninsula (first from Portugal, then from Spain).

i'm sure the answer you are looking for would be

a. an ice age

hope this contact me if this didn't or you need with more answers : )