What did the monroe doctrine prohibit european countries from doing

In the mid-1800s, native americans who had lived in the westtraded their manufactured goods with settlers.were able to resist diseases carried by settlers.offered their services as guides to settlers.prevented settlers from moving onto their territory.

Which of these belongs to the united states after the spanish american war ?

How does the concept of competition relate to the arms race between the us and the soviet union during the cold war?