Final answer:
The state and federal governments supported the construction of canals in the early to mid-1800s to improve trade by reducing transportation costs.
Step-by-step explanation:
In the early to mid-1800s, both the state and federal governments supported the construction of canals for several reasons. One major reason was to improve trade by reducing transportation costs. Canals provided a more efficient and cost-effective means of transporting goods compared to overland routes, which were slow and expensive. By connecting major waterways, such as the Erie Canal in New York, canals allowed goods to be transported from the Eastern states to the West and vice versa, facilitating trade and economic growth.