Economy

Economy refers to the human activities related with the production, distribution, exchange, and consumption of goods and services. However, its definition transformed throughout history with the activities attributed to economy. The composition of a given economy is inseparable from civilization's history and social organization, and from Earth's geography and ecology, e.g. ecoregions which represent different agricultural and resource extraction opportunities, among other factors.
The fields of study exploring, registering and describing the economy or a part of it, belong in general to the social sciences and include economics as well as branches of history (economic history) or geography (economic geography). Subgroups of economics are macroeconomics, microeconomics, econometrics, national economy, political economy, classical economy, economic anthropology, economic democracy and more. Economic measures such as the Gross Domestic Product (GDP) are part of econometrics. Practical fields more directly related to the human activities involving production, distribution, exchange, and consumption of goods and services as a whole, range from engineering to management and business administration to applied science to finance. Consumption, saving and investment, are core variable components in the economy and determine equilibrium in the markets. There are three main sectors of economic activity: primary, secondary and tertiary.