<Li> Balance of Trade </Li> <P> The GDP - Gross domestic product of a country is a measure of the size of its economy . The most conventional economic analysis of a country relies heavily on economic indicators like the GDP and GDP per capita . While often useful, it should be noted that GDP only includes economic activity for which money is exchanged . </P> <P> An informal economy is economic activity that is neither taxed nor monitored by a government, contrasted with a formal economy . The informal economy is thus not included in that government's gross national product (GNP). Although the informal economy is often associated with developing countries, all economic systems contain an informal economy in some proportion . </P> <P> Informal economic activity is a dynamic process which includes many aspects of economic and social theory including exchange, regulation, and enforcement . By its nature, it is necessarily difficult to observe, study, define, and measure . No single source readily or authoritatively defines informal economy as a unit of study . </P>

Explain three types of economic activities with example