Final answer:
The most devastating factor responsible for the 90% decrease in Native American populations was the introduction of bacterial and viral diseases by European settlers, which native populations had no immunity to. Additionally, changes imposed by European colonization weakened the communities, increasing vulnerability to disease.
Step-by-step explanation:
The devastation of over 90% of the Native American population was caused largely by bacterial and viral diseases introduced by European settlers. Europeans had developed resistances to many of these diseases over the centuries, but the Indigenous peoples of the Americas, having had no prior exposure, lacked immunity. Diseases such as smallpox, typhus, measles, bubonic plague, and influenza ravaged the populations and claimed the lives of millions.
Additional hardships were brought on by the environmental changes and new societal structures imposed by European colonization. These changes further weakened the Native American communities, making them more susceptible to infections. Consequently, infectious diseases spread rapidly in populated regions, often wiping out entire populations.
It is also important to note that while European diseases played a significant role, other factors such as warfare, forced labor, and the depletion of natural resources also contributed to the devastation.
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