How did U.S. government policies towards Native Americans change during this period?

During this period, U.S. government policies towards Native Americans indeed shifted towards assimilation and land allotment. This approach was exemplified by the Dawes Act of 1887, which aimed to break up tribal lands into individual allotments for Native Americans and promote assimilation into American society. The idea was that by giving individual Native Americans ownership of land, they would be encouraged to adopt farming practices and integrate into the dominant European-American culture.

This reflected a broader trend in U.S. policies during the late 19th and early 20th centuries, where the government viewed Native American cultures as obstacles to progress and sought to "civilize" them through education and land ownership. Schools were established to educate Native American children in Western values and customs, further supporting the goal of assimilation.

In contrast, while there were periods and instances of violence and conflict leading to the extermination of certain tribes and individuals, this was not the sole focus of policy during this time. Rather, the culmination of policies often led to a systematic dismantling of tribal lands and cultures, rather than outright extermination. Hence, the key shift was toward promoting assimilation and land allotment rather than allowing for tribal autonomy or independence, as indicated by the correct choice.