According to the open systems perspective, resources are transformed into that are exported to the external environment.

The business cycle is the periodic but irregular up-and-down movement in economic activity, measured by fluctuations in real gross domestic product (gdp) and other macroeconomic variables. a business cycle is typically characterized by four phases—recession, recovery, growth, and decline—that repeat themselves over time. economists note, however, that complete business cycles vary in length. the duration of business cycles can be anywhere from about two to twelve years, with most cycles averaging six years in length. some business analysts use the business cycle model and terminology to study and explain fluctuations in business inventory and other individual elements of corporate operations. but the term "business cycle" is still primarily associated with larger (industry-wide, regional, national, or even international) business trends.

In line with other previous and contemporaneous proposals, in 1912 the meteorologist  alfred wegener  amply described what he called continental drift, expanded in his 1915 book the origin of continents and oceans and the scientific debate started that would end up fifty years later in the theory of plate tectonics.