Final answer:
Plains Indians lived in teepees, which were portable conical tents made of animal skins or bark-covered poles.
Step-by-step explanation:
The type of structure that Plains Indians lived in was called a teepee. A teepee is a conical tent traditionally made of animal skins or bark-covered poles, and it was used by many Native American tribes, including the Plains Indians. The teepee was a portable and practical shelter, which made it well-suited for the nomadic lifestyle of the Plains Indians.
Learn more about Plains Indians and their dwellings