The correct answer is C) horses.
Before 1800, the European import that had the greatest impact on the lives of the Plains Indians was horses.
Although hard to believe, horses did not exist in the Americas. It was the European Spanish conquerors who brought horses to the American continent. When the first Native American Indians saw the horses, they thought they were deers, the most alike animal they knew.
So horses were very useful for Native American Indians tribes in that they used to move faster from one place to the other, to better hunt Buffaloes, to transport heavy loads, and also were used in war.
