Question

What were Native American groups most threatened by? buffalo herds other Native American groups drought diseases introduced by white settlers

Answer 1

Diseases introduced by white settlers.
The main reason for the wipe-out of Native Americans was the threat of the diseases introduced by White Europeans. This ended up killing many Native Americans across different tribes, as they had no immunity to these diseases and had never dealt with these kinds of illnesses before. This was a rampant problem and attained the Native Americans quickly after the European settlers arrived.

Answer 2

Diseases introduced by white settlers.