Summarize the reasons native american culture was irrevocably changed by the end of the 1800s culture

The native cultures of North America could not be preserved as they were originally, first by the wars that the colonists and then the Americans, held against them; then, when their lands were bought, and the tribes moved to Indian reservations, their native land and their ancestral forms of life were changed or finished; then, being unable to live on the hunt, and losing the lands that were before them, they had to have modern jobs, to leave some traditions, to change their way of life; and in addition to this, some have adopted customs, ideas, or the religion of the Americans.