<P> North America has been historically referred to by other names . Spanish North America (New Spain) was often referred to as Northern America, and this was the first official name given to Mexico . </P> <P> Geographically the North American continent has many regions and subregions . These include cultural, economic, and geographic regions . Economic regions included those formed by trade blocs, such as the North American Trade Agreement bloc and Central American Trade Agreement . Linguistically and culturally, the continent could be divided into Anglo - America and Latin America . Anglo - America includes most of Northern America, Belize, and Caribbean islands with English - speaking populations (though sub-national entities, such as Louisiana and Quebec, are Francophone in composition). </P> <P> The southern North American continent is composed of two regions . These are Central America and the Caribbean . The north of the continent maintains recognized regions as well . In contrast to the common definition of "North America", that which encompasses the whole continent, the term "North America" is also used to refer to Canada, Mexico, the United States, and Greenland . </P> <P> The term Northern America refers to the northern-most countries and territories of North America, Canada, the United States, Greenland, Bermuda, and St. Pierre and Miquelon . Although rarely used, the term Middle America--not to be confused with the Midwestern United States--groups the regions of Central America, the Caribbean, and Mexico . </P>

What is the largest source of north america's population growth