Before the arrival of Europeans, the American Indian tribes were highly tribal and nomadic in nature.
Most of them had bitter rivalries with one another and small skirmishes were commmon.
However, after the Europeans arrived, many of these tribes felt threatended and began to form alliances. The alliances helped to muster up bigger numbers for a prolonged war that greatly effected the expansion of European power for a while.
Eventually, the American Indian tribes lost. They were subjected to end their nomadic lifestyle, settle in cities and gradually adopted English language and culture.
<span>Assuming that this is referring to the same region that was posted before with this question, <span>the correct response would be that the encroachment of Europeans forced many native tribes that had up until this point been rivals to form alliances in order to stop the spread of European settlement. </span></span>