One reason the cultures of north africa developed differently from the cultures of the rest of africa was that these areas of africa were separated by the a) arabian sea. b) sahara desert. c) congo river basin. d) great rift valley.

The correct answer is B. Sahara Desert.

Explanation

Africa is a continent of planet Earth, in this, the Sahara desert is located which is considered as the largest in the world as its extension is around 9 million km². Additionally, this desert separates the North and South fo Africa and crossing it implies being exposed to extreme weather conditions and lack of resources. As a result of this, historically cultures of the north could not easily interact with the cultures of the south, for this reason, a tribal development was evident in the south, while in the north along the entire Mediterranean coast, cultures became great civilizations such as the Egyptian and Roman. So, the correct answer is B. Sahara Desert

no , per capita income is not a true measure of the development because: -it only tells us about average income not how income is distributed among the people.it only give us an idea of the economic aspect.it is only at the qualitative basis.moreover, income is not only the way of development other factors are also as much as important as income.