Final answer:
The North's major economic activity before the Civil War was manufacturing and industry, powered by technological advances and an extensive railroad network, whereas the South relied on agriculture and farming. Option A is correct.
Step-by-step explanation:
Before the Civil War, the North's major economic activity was centered on manufacturing and industry. Many significant industrial factories were located in the northern states, leveraging large rivers for transportation and technological innovations such as the steamboat and telegraph for communication and movement of goods.
The North excelled in the mass manufacture of items including clothing, aided by inventions such as the sewing machine, and created a robust industrial environment. In contrast, the southern states' economy was primarily based on large agricultural plantations supported by slave labor, which grew cotton for the northern mills and tobacco for export.
The railroads played a crucial role in the expansion and mobilization of the United States, particularly for the North, where they allowed for the rapid movement of men and materials, especially during the Civil War.
The North's larger population and superior industrial capabilities, including extensive railroad networks, gave it the upper hand in mobilizing resources and sustaining the war effort against the South.
The South, reliant on agriculture and farming with a focus on plantation crops like cotton and tobacco, lacked significant urbanization or industrialization at the time.