The high incidence of disease spread from Europeans to
American Indian populations
weakened American Indian tribes significantly, making them more vulnerable to European invasion.
Explanation:
The population of American Indian tribes was greatly decimated by diseases, especially smallpox and other communicable diseases. Most of the diseases were brought by the Europeans who had developed immunity to the diseases, and as a result did not suffer from the diseases but were able to spread the diseases whenever they had contact with the native Indian tribes.
