1) The correct answer is Sitting Bull and George Custer.
Sitting Bull lead the Sioux tribe at the Battle of Little Big Horn, which took place in the territory of Montana near the Little Big Horn lake. George Custer was the leader of the American troops. This military victory for the Native Americans resulted in the death of George Custer and other American military officers. This is why this battle is also referred to as Custer's Last Stand.
2) The correct answer is the Dawes Act.
The Dawes Act took Native American land on reservations and gave it to individual family units. This was a major change as this reservation land used to be owned communally. Communal land owning is an idea that all citizens of a community have equitable access to all parts of the land.