Research online (or perhaps you have your own example?), then explain which of the concepts was selected, explain the details of the concept and then provide an example of the concept.

Immigration: The recent level of U.S. Immigration is at a historically high level if we measure it in absolute numbers, but not if we measure it as a share of population. The overall gains to the U.S. economy from immigration are real but relatively small. However, immigration also causes effects like slightly lower wages for low-skill workers and budget problems for certain state and local governments.