How is the GDP of a country calculated like is a research conducted or a survey done or something else?

The following equation is used to calculate the GDP: GDP = C + I + G + (X – M) or GDP = private consumption + gross investment + government investment + government spending + (exports – imports). ... It transforms the money-value measure, nominal GDP, into an index for quantity of total output.

Ithink that it’s mali

Answer// dinosaurs emerged during mesozoic era;