Final answer:
Slavery evolved in the U.S. from a system alongside indentured servitude to an economy-central institution, especially in the South due to the cotton industry. The North started abolishing slavery due to different economic needs, leading to a sectional divide that heightened tensions and paved the way for conflict.
Step-by-step explanation:
Slavery in the United States evolved over time, with significant differences observed in slave societies in the 17th and 18th centuries. Initially, slavery existed alongside indentured servitude, but with the development of plantation economies, it became entrenched, especially in the South.
The North began gradually abolishing slavery post-American Revolution due to smaller agricultural operations and different economic structures. Contrastingly, slavery became a way of life in the more agrarian South, where it supported the profitable cotton industry and other cash crops, manifesting in a deep reliance on slave labor.
By the 1790s, the invention of the cotton gin rejuvenated slavery and led to its westward expansion. Northern states, which had begun the process of abolition, feared that slavery would suppress free labor wages and advocated for its containment. Southern states, however, feared that restrictions on slavery's growth would intensify abolitionist influence and lead to social upheaval.
This regional divergence contributed to a sectional crisis, heightening tensions between the North and South. Consequently, the economic, social, and political climates in these areas diverged markedly, setting the stage for conflict.