Answer:
A. Disease, land loss, and a shrinking Native population
Explanation:
When the Europeans started migrating to the Americas and claiming it as there's, they brought over disease and etc. These diseases didn't affect the Europeans because their immune system was used to it and adapted to those bacteria's and disease but the Native Americans weren't. The diseases brought over by the European started killing them off to the point where there were very few left. As the Europeans came, they claimed the Natives land for themselves, using it for whatever they needed and felt necessary.
