Need for a way to measure a nation's income and output.
Explanation:
The Gross Domestic Product of a nation is a unit of macroeconomic measurement that represents the amount of goods and services produced within the territory of a nation during a given period of time. Thus, the value of each of these goods and services are added together, and the numerical total of said sum thus represents the total value of production of said country during the year.
Primary prevention—those preventive measures that prevent the onset of illness or injury before the disease process begins. Examples include immunization and taking regular exercise.
