Which is the most important factor leading to the reduction of native populations that could be added to Las Casas' first-hand account?

The reduction of native populations in the Americas was significantly influenced by the introduction of nonnative diseases by the Spanish. This factor had a catastrophic impact on indigenous peoples, as they had no prior exposure or immunity to diseases such as smallpox, influenza, and measles. These diseases spread rapidly and led to widespread mortality among native populations, decimating communities and disrupting social structures.

Las Casas' account documents the profound effects of European contact and highlights the tragic consequences of disease. The devastating impact of introduced diseases was often more lethal than violence or conflict, ultimately leading to significant demographic changes. This historical phenomenon illustrates the consequences of colonization beyond mere conquest, showing how diseases altered the landscape of human populations and transformed entire societies.