True or false. pollution was a problem in medieval towns. if false why?

Prior to the presence of europeans on the continent, the slave trade in africa a) did not exist in any form. b) was limited to internal trade only. c) included the trans-saharan and indian ocean slave trade. d) was rarely needed due to the lack of an agricultural economy.

Somebody save the ! what was greek math and science also medicine

How did the incas unite the andes mountains?