Final answer:
The decline of indigenous populations due to disease and harsh conditions, along with the unsuitability of European indentured servants, led Europeans to rely on African slaves, who were viewed as more resilient and could be enslaved for life, for labor in the Americas.
Step-by-step explanation:
Europeans gradually ceased using indigenous slaves in North America and the Caribbean due to a drastic decline in the native population caused by disease, violence, and harsh labor conditions. Native populations were decimated by infectious diseases to which they had no immunity, such as smallpox and influenza. For example, the Taíno population on Hispaniola plummeted from several hundred thousand in 1492 to about thirty-two thousand by 1514. Consequently, there were not enough indigenous people left to perform the labor-intensive work required on the vast plantations.
Furthermore, the high mortality rates among European indentured servants due to the hot climate and diseases such as malaria and yellow fever made them an unreliable labor source. Laws such as the French decree restricting the violence against indentured servants also contributed to Europeans turning away from this form of labor. African slaves, on the other hand, had developed some immunity to European diseases and were thus seen as more resilient. They could be enslaved for life, ensuring a consistent labor force for the massive plantations that produced sugar, coffee, rice, and cotton.
Ultimately, the need to maintain a profitable and robust labor force led European colonists to rely on the Trans-Atlantic slave trade, acquiring slaves through trade with West African kingdoms. This devastating trade saw approximately 12 million Africans forcibly transported across the Atlantic, with around 4 million dying en route. African slaves became the primary labor force in the Americas due to their perceived physical suitability, the potential for lifetime enslavement, and their established skills in agriculture and animal husbandry.