Ivory and gold are both items the Aksum sold; I am not sure if the correct answer is cotton or salt. Cotton is believed to have originated in the Indus Valley, and I know salt was a major trade item in Ghana. If you know that Ghana and the Askum people traded with each other, then you know they were not involved in trading cotton.
It is definetly c. I think the question is should be conservation in America.
Because conservation generally talks about biodiversity,Environmental and natural resources
