Answer: Beginning in the a.d. 600s until about the 1000s, Berber traders carried salt southward across the Sahara, where they traded it for gold. They then returned across the Sahara to North Africa. Merchants in Ghana brought gold from the south and traders brought salt from the north. The salt-for-gold trade was carried on with the kingdom of Ghana. Ghana grew rich by taxing these purchases. After Ghana lost power, trade took place with the kingdom of Mali.
Islam was the religion practiced in North Africa. Over time, the Berbers adopted the religion too. By doing business in trading centers in West Africa, the Berbers introduced Islam there as well. The spread of religion along trade routes is one example of cultural diffusion.
Explanation: In cultural anthropology and cultural geography, cultural diffusion, as conceptualized by Leo Frobenius in his 1897/98 publication Der westafrikanische Kulturkreis, is the spread of cultural items—such as ideas, styles, religions, technologies, languages—between individuals, whether within a single culture or from one culture to another. It is distinct from the diffusion of innovations within a specific culture. Examples of diffusion include the spread of the war chariot and iron smelting in ancient times, and the use of automobiles and Western business suits in the 20th century.
Extra explanation: Impact of cultural diffusion is when new technologies are shared around the world. Inventions such as the telescope, the printing press, steam engines, cars, and computers have all had big impacts on how people live in every area of the world.
