Final answer:
Agriculture and manufacturing are major industries in the Great Lakes St. Lawrence Lowlands with tourism also on the rise.
Step-by-step explanation:
One of the main industries in the Great Lakes St. Lawrence Lowlands is agriculture, especially in the province of Ontario which has fertile farmland on the north and east sides of the Great Lakes. Additionally, the St. Lawrence River region is known for its dairy farms and agriculture which supply food to the larger cities.
Beyond agriculture, the area has developed a significant manufacturing sector with Montreal emerging as a diverse industrial center, featuring oil refineries steel mills and more. Tourism has also become an increasingly important industry in the region.