Which explains how the treaty at the Walla Walla Council affected the Nez Perce?

The 1855 treaty at the Walla Walla Council set aside a reservation for the Nez Perce while requiring them to give up much of their ancestral territory. It also restricted their traditional seasonal movement across different parts of their homeland. So the choice describing a small reservation and the loss of seasonal movement is correct.

AI-written and checked against the verified answer.