Which of the following is not an advantage of a price based system

Rock concerts musical instruments cell phones and contact lenses are just a few things that are possible because of

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.

Why do you think americans were so fascinated by this idea of the united states stretching from “sea to sea”? give 2 reasons