<P> Almost every system of organization applied to the world is arranged hierarchically . By their common definitions, every nation has a government and every government is hierarchical . Socioeconomic systems are stratified into a social hierarchy (the social stratification of societies), and all systematic classification schemes (taxonomies) are hierarchical . Most organized religions, regardless of their internal governance structures, operate as a hierarchy under God . Many Christian denominations have an autocephalous ecclesiastical hierarchy of leadership . Families are viewed as a hierarchical structure in terms of cousinship (e.g., first cousin once removed, second cousin, etc .), ancestry (as depicted in a family tree) and inheritance (succession and heirship). All the requisites of a well - rounded life and lifestyle can be organized using Maslow's hierarchy of human needs . Learning must often follow a hierarchical scheme--to learn differential equations one must first learn calculus; to learn calculus one must first learn elementary algebra; and so on . Even nature itself has its own hierarchies, as numerous schemes such as Linnaean taxonomy, the organization of life, and biomass pyramids attempt to document . Hierarchies are so infused into daily life that they are viewed as trivial . </P> <P> While the above examples are often clearly depicted in a hierarchical form and are classic examples, hierarchies exist in numerous systems where this branching structure is not immediately apparent . For example, most postal code systems are hierarchical . Using the Canadian postal code system as an example, the top level's binding concept is the "postal district", and consists of 18 objects (letters). The next level down is the "zone", where the objects are the digits 0--9 . This is an example of an overlapping hierarchy, because each of these 10 objects has 18 parents . The hierarchy continues downward to generate, in theory, 7,200,000 unique codes of the format A0A 0A0 (the second and third letter position allow 20 objects each). Most library classification systems are also hierarchical . The Dewey Decimal System is regarded as infinitely hierarchical because there is no finite bound on the number of digits can be used after the decimal point . </P> <P> Organizations can be structured as a dominance hierarchy . In an organizational hierarchy, there is a single person or group with the most power and authority, and each subsequent level represents a lesser authority . Most organizations are structured in this manner, including governments, companies, militia and organized religions . The units or persons within an organization are depicted hierarchically in an organizational chart . </P> <P> In a reverse hierarchy, the conceptual pyramid of authority is turned upside - down, so that the apex is at the bottom and the base is at the top . This model represents the idea that members of the higher rankings are responsible for the members of the lower rankings . </P>

How the division of power between higher and lower level of government is known as