How did the American indian populations numbering in the millions fall under the dominance of much smaller groups of Europeans?

D) diseases wiped out great numbers of Americans Indians.

Explanation:

American Indian populations numbering in the millions fall under the dominance of much smaller groups of Europeans because diseases wiped out great numbers of Americans Indians.

Native American Indians were clean, healthy people that had good habits and were used to take from the Earth what they needed. But when the European conquerors arrived at the American territories, they brought with them a series of diseases unknown to the American Indians, and that is why they were not immune to these diseases. Among those diseases brought by the European people are bubonic plague, cholera, typhus, chickenpox, diphtheria, pneumonia, measles, influenza, smallpox, and tuberculosis.

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