What natural advantage did the kingdoms of west africa have?

a. an abundance of fertile soil for cash crops b. an abundance of natural resources including salt and gold c. large mountains that protected the kingdom from invasion d. larger-than-average people who made good soldiers

One natural advantage that the kingdoms of West Africa had was "B. An abundance of natural resources including salt and gold," which is why it became such a popular trading area. 

They said that the world was flat

Cherokee  removal, part of the trail of tears, refers to the  forced  relocation between 1836 and 1839 of thecherokee  nation from  their lands ingeorgia, south carolina, north carolina, tennessee, texas, and alabama to the indian territory (present day oklahoma)  in  the thenwestern united states, and the resultant deaths