Final answer:
Anthropologists of the 19th century believed in a theory called unilineal evolutionism, which stated that cultures transformed over time into more complex and superior cultures. However, this theory has been largely abandoned by modern anthropologists.
Step-by-step explanation:
Many anthropologists of the 19th century believed that cultures transformed over time into more complex and superior cultures. This type of thinking is called unilineal evolutionism. It was a theory that argued that all cultures progressed through a set of stages, with some cultures being more advanced than others. However, this theory has been largely abandoned by modern anthropologists.