What technology did city planners adopt when attempting to meet the needs of commuters?

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.

Space is not completely empty. there are small particles in space. what happens when these particles come together?

Name three new weapons that changed how ww! was fought and how?