Final answer:
The correct answer is option c. The primary cause of death among American Indians during European colonization was European diseases like smallpox, diphtheria, and measles, to which Native Americans had no immunity, resulting in widespread mortality.
Step-by-step explanation:
The leading cause of death among American Indians during European colonization was not war, malnutrition, lack of clean water, nor forced removal. It was the introduction of European diseases, such as smallpox, diphtheria, and measles. The indigenous peoples had no prior exposure or immunity to these diseases, which allowed them to spread rapidly and with devastating effects. Studies suggest that Native American populations decreased dramatically from an estimated 12 million in 1500 to around 237,000 by 1900.
The spread of diseases like smallpox was catastrophic because Native Americans had no immunity, resulting in high mortality rates, particularly among the very young and the very old. This loss not only reduced numbers but also severed cultural and traditional knowledge. The high death toll from these diseases, along with other factors such as enslavement, forced relocations like the Trail of Tears, and the destruction of livelihoods, contributed to what some historians describe as a genocide against Native American tribes.