The Public Sector or state sector (which usually includes: parliament, law-courts and government centers, various emergency services, public health, shelters for empoverished and threatened people, transport facilities, air/sea ports
(A logging company might research ways to use partially burnt wood to be processed so that the undamaged portions of it can be made into pulp for paper.)
Quaternary stage/degree of the economy: Involves the research and development needed to produce products from natural resources and their subsequent by-products.
Tertiary stage/degree of the economy: Involves the provision of services to consumers and businesses, such as baby-sitting, cinema and banking.
Primary stage/degree of the economy: Involves the extraction and production of raw materials, such as corn, coal, wood and iron. (A coal miner and a fisherman would be workers in the primary degree.)
The secularization in Europe allowed states to use the immense property of the church for the development of towns.
For most people the exchange of goods occurred through social relationships. There were also traders who bartered in the marketplaces.
Several centuries after the invention of cuneiform, the use of writing expanded beyond debt/payment certificates and inventory lists to be applied for the first time, about 2600 BC, to messages and mail delivery, history, legend, mathematics, astronomical records and other pursuits.
The Babylonians and their city state neighbors developed forms of economics comparable to currently used civil society (law) concepts
All professions, occupations, economic agents or economic activities, contribute to the economy. Consumption, saving, and investment are variable components in the economy that determine macroeconomic equilibrium.