A subsistence economy is a non-monetary economy which relies on natural resources to provide for basic needs, through hunting, gathering, and subsistence agriculture. "Subsistence" means supporting oneself at a minimum level; in a subsistence economy, economic surplus is minimal and only used to trade for basic goods, and there is no industrialization.
In the history of the world, before the first cities, all humans lived in a subsistence economy. As urbanization, civilization, and division of labor spread, various societies moved to other economic systems at various times. Some remain relatively unchanged, ranging from uncontacted peoples, to poor areas of developing countries, to some cultures that choose to retain a traditional economy.
Capital can be generally defined as assets invested with the expectation that their value will increase, usually because there is the expectation of profit, rent, interest, royalties, capital gain or some other kind of return. However, this type of economy cannot usually become wealthy by virtue of the system, and instead requires further investments to stimulate economic growth. In other words, a subsistence economy only possesses enough goods to be used by a particular nation to maintain its existence and provides little to no surplus for other investments.