LIFE SCIENCE

Detailed explanation-1: -Persons per square mile-population and housing unit density are computed by dividing the total population or number of housing units within a geographic entity by the land area of that entity measured in square miles or in square kilometers.

Detailed explanation-2: -In the U.S., population density is typically expressed as the number of people per square mile of land area. The U.S. value is calculated by dividing the total U.S. population (316 million in 2013) by the total U.S. land area (3.5 million square miles).

Detailed explanation-3: -A high population density implies that the population is high relative to the size of the country. Countries, such as Belgium and the Netherlands have a high population density. Large countries, such as Australia and Canada have very low densities.