What is astronomy and what tool are used

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.

Surfaces of paintings—such as paper, canvas, and pottery—are referred to technically as

We belong to many different social groups that are made up of people that we interact with regularly. choose one of the following social groups: family friends co workers which social group has influenced you the most? in what ways?