Final answer:
The key products from southern Ontario that are among Canada's key exports are automobiles and machinery.
Step-by-step explanation:
The key products from southern Ontario that are among Canada's key exports are automobiles and machinery.
These industries have a significant presence in southern Ontario, particularly in cities like Toronto and Windsor.
The automobile industry includes major manufacturers such as General Motors and Ford, while the machinery industry includes companies that produce equipment for various sectors like agriculture and mining.