According to the text, ______ borders affect how and where humans have settled and the degree to which they interact with one another.

The use of control variables for testing the relationship between

diversity and democracy: a. rules out other independent variables that might be affecting the level of democracy. b. examines the relationship between the control variable and democracy. c. examines the relationship between the control variable and diversity. d. controls the results they want to find.

A class approach to the study of politics is based upon the notion of stratification. This means that

A. some classes are made up of a single occupational group. B. some classes are divided on the basis of gender. C. some classes have more rights than others simply because of their class identity. D. some classes are insulated from economic factors in society.