Which statement correctly describes the region of africa?

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.

The patriot act made it easier for law enforcement agencies to conduct surveillance under certain circumstances true or false

Suppose you are a freshmen in college and you have not declared a major. one reason you enrolled at your respective college was the school's vibrant social life. at the same time, you want to balance your academic life because you know that your grades will matter for graduate school or job applications. you decide to forgo partying for two hours to study for an upcoming economics exam. in your first semester's principles of economics class, you learn that the enjoyment you would have received from partying is an example of a(n)