The world economy or global economy is the economy of all humans in the world, referring to the global economic system, which includes all economic activities conducted both within and between nations, including production, consumption, economic management, work in general, financial transactions and trade of goods and services. In some contexts, the two terms are distinct: the "international" or "global economy" is measured separately and distinguished from national economies, while the "world economy" is simply an aggregate of the separate countries' measurements. Beyond the minimum standard concerning value in production, use and exchange, the definitions, representations, models and valuations of the world economy vary widely. It is inseparable from the geography and ecology of planet Earth. It is common to limit questions of the world economy exclusively to human economic activity, and the world economy is typically judged in monetary terms, even in cases in which there is no efficient market to help valuate certain goods or services, or in cases in which a lack of independent research, genuine data or government cooperation...