Final answer:
The increase in international trade in Canada since 1989 was mainly caused by the free trade agreement between Canada and the United States, alongside subsequent agreements such as NAFTA.
Step-by-step explanation:
What partly caused the increase in international trade in Canada since 1989? The primary cause of this was d. the free trade agreement between Canada and the United States, known as the Canada-US Free Trade Agreement (Canada-US FTA). Implemented in 1988, it significantly reduced trade barriers between the two nations. Additionally, later agreements such as the North American Free Trade Agreement (NAFTA), which includes Mexico, further cemented regional economic integration and facilitated more open and efficient trade across North America, helping to increase international trade for Canada.
Despite the potential influence of other factors like an appreciation of the Canadian dollar, improved quality of Canadian products, or changes in Canadian GDP, the trade agreements have played a pivotal role in enhancing international commerce by removing tariffs and reducing restrictions on the movement of goods and services.