Final answer:
The Ancestral Pueblo people lived in the four-corners area from 700 CE to 1300 CE, and their civilization was at its height in 1450 CE as indicated by their elaborate cliff dwellings in Mesa Verde National Park.
Step-by-step explanation:
The Ancestral Pueblo people lived in the United States in the four-corners area from approximately 700 CE to 1300 CE. The height of their civilization can be best associated with the date 1450 CE. During this time, they lived in elaborate cliff dwellings in Mesa Verde National Park, Colorado, as evident from the archaeological remains found.