Complex sentence: The Ancestral Puebloans were one of four major prehistoric archaeological traditions recognized in the American Southwest, sometimes referred to as Oasisamerica in the region defining pre-Columbian southwestern North America.
Split into simpler sentences: The Ancestral Puebloans were one of four major prehistoric archaeological traditions recognized in the American Southwest. This area is sometimes referred to as Oasisamerica in the region defining pre-Columbian southwestern North America.