2.1-2.2

• population distribution - pattern of human settlement; spread of people across earth
• population density - average population per square mile or kilometer of an area
• midlatitudes - regions between 30°-60°, north and south of the equator
• low-lying areas - areas that are below sea level and are prone to flooding
• social stratification - the division of society into different social classes based on wealth, occupation, education, and other factors
• arithmetic population density - calculated by dividing a regions population by its total area
• physiological population density - total population divided by the amount of arable land
• agricultural population density - compares number of farmers to arable land
• redistricting - redrawing district boundaries so each district contains roughly the same population
• carrying capacity - the maximum number of individuals that an ecosystem can support