In this simple economic model with a closed economy there are three uses for GDP, (the goods and services it produces in a year). If Y is national income (GDP), then the three uses of C consumption, I investment, and G government purchases can be expressed as:National savings can be thought of as the amount of remaining money that is not consumed, or spent by government.ational savings should be split into private savings and public savings. A new term, T is taxes paid by consumers that goes directly to the government as shown here: (Y-T) is disposable income. (Y-T) less consumption (C) is private savings.
Canada is not part of the USA but Canada has border with the United States; however, Canada is a total different country with its own regulations.
America I suppose is relating more to the continent (North America/South America). The USA is part of North America, but people just call the USA 'America' for short. So if someone says they're going to America, or that they live in America, they're probably referring to the USA, not the continent.