Explain how supply and demand work together to determine prices of a good or service

When zhang qin went to explore west, he brought back stories of

Imagine a child who consistently gets mediocre grades and is often picked last for a team when games are played at recess. however, he likes to make silly jokes and play pranks, and he notices that people laugh when he does those things. the child starts to think that others are laughing with him, not at him. this is part of the process that charles cooley

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.