They were mainly agriculture based and slavery was free labor.
Code talkers transmitted messages over military telephone or radio communications nets using formally or informally developed codes built upon their native languages. The code talkers improved the speed of encryption and decryption of communications in front line operations during World War II
Answer:
A)a trade route
Explanation:
we just went over this in school today
It enabled civilizations around rivers to emerge because it enabled them to grow their own food in fertile lands. It also enabled class division to emerge into those who dealt with trade and those grew food. It also enabled rise of political system like monarchies with rulers and dynasties.