Ihave to put wages and risk in one sentence

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.

During the 1500s,most rulers supported established a. political systems. d. none of the above b. churches c. freedom of speech

Why do you think that historians use the word “revolution” to describe important changes in agriculture? how did the green revolution and other agricultural revolutions change the lives of billions of people? < < read less