What greek scientist created a screw to move water for irrigation?

Which of the following was a key accomplishment of the people of songhai? a. they had a strong military and became the largest empire in west africa. b. they established a center of islamic scholarship. c. they worked with iron and prospered from the gold-salt trade. d. they dominated in the trade of ivory, enslaved people, and animal skins.

Which groups of people most directly benefited from song innovations in the song dynasty‘s open border policy?

On this map, the state of georgia is in which section of the map?