Missisipi river is the answer pal
Efficient government and adequate rulers
Answer:
The opponent process theory suggests that the way humans perceive colors is controlled by three opposing systems. We need four unique colors to characterize perception of color: blue, yellow, red, and green. According to this theory, there are three opposing channels in our vision.
Explanation:
Answer:
Probably trading pottery and stone vases for ivory and metals.
Explanation: