Final answer:
Developing the system of roads in the early nineteenth century helped the country transition from a subsistence economy to a market economy.
Step-by-step explanation:
Developing the system of roads in the early nineteenth century greatly affected the economy by helping the country transition from a subsistence economy to a market economy. With the construction of roads and turnpikes, transportation became more efficient and reliable, allowing for the transportation of goods and people over long distances. This expansion of transportation infrastructure facilitated trade, connected different regions, and enabled the growth of a national market system.