According to myth, why did the gold trade decline in ghana?

According to myth, the dead of the Bida originated the decline in gold trade in Ghana.

Explanation:

The reason behind this is that first of all the trade allowed them to exchange salt for gold. Also, Egyptians were always eager to acquire as much as they could because gold was a really important element in their culture. But the death of the Bida was the myth that caused the decline of the gold trade in Ghana due to the importance of the empire to Ghana. It is said that after they fell the region changed completely.  

the dust bowl, otherwise known as the dirty thirties, was a huge dust storm that killed multiple (and i mean  multiple) farmer's crops, leaving them homeless, and foodless, and jobless. in california, there were 5.7 million residents, and the population shrank as mexicans were repatriated. however, when the dustbowl happened, a lot of people began to move to california. by 1940, 250,000 people had arrived. therefore, your answer would be  the population increased, massively.  i hope this !

explanation:

sonar maybe? ? i dont know the choices