Working hard for another in return for protection best describes what element of the Middle Ages? A. chivalry
B. feudalism
C. the Church
D. manorialism

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.