Questions:
1. Angola and Chad
2. Ethiopia and Sudan
3. Mauritania and Niger

What is the role of buyer & seller in the marketplace

How does cultural diffusion affect civilization

Which statement is a good description of a model? a) models are a description of nature based only on one or two variables. b) models are testable ideas but they are not very to most people. c) models are a description of nature that predicts more accurately than real events. d) models are an approximiation of a real system that omits all but most essential variables in a system.