Final answer:
The land surrounding the St. Lawrence River and Great Lakes is Canada's heartland due to its fertile farmland, pivotal historical role, strong French-Canadian cultural presence, and its valuable natural resources supporting various industries.
Step-by-step explanation:
The land surrounding the St. Lawrence River and Great Lakes is called the heartland of Canada because it is highly significant for the country's agriculture, industry, and history. This region is the core of French Canada, housing the St. Lawrence Valley, which is central to the French-Canadian culture. The fertility of the land in this area contributes to some of Canada's best farmland with dairy farms along the St. Lawrence River and agriculture that provides food for major cities.
The region's importance is not only economic but historical as well. After the colonization by the French and despite the transfer to Great Britain following the French and Indian War, the presence of French inhabitants has persisted. This has led to a robust French-Canadian culture, with a prevalence of French speakers, especially in Quebec.
The area is also a hub for a variety of industries thanks to the abundance of natural resources like timber, minerals, and hydroelectric power. Cities like Montreal have developed as major industrial and economic centres because of the strategic access provided by the St. Lawrence River and the Great Lakes. Moreover, Montreal is significant for being the largest French-speaking city in the Western hemisphere.