Final answer:
American anthropology was largely developed by Franz Boas at Columbia University where he established significant methodological foundations for the field and advocated against racism.
Step-by-step explanation:
The true statement about American anthropology among the provided options is that it was first developed under Franz Boas at Columbia University. Franz Boas, often considered the father of American anthropology, promoted a holistic approach integrating the four fields of anthropology and challenged the prevailing race theories of his time, highlighting the environmental influence on human development.
Boas's career was largely defined by his role as an anthropology professor at Columbia University and his significant contributions to the field. He conducted extensive fieldwork and put emphasis on obtaining ethnographical information directly from indigenous peoples. His approach transformed anthropology, making it more empirical and less speculative, and he strongly advocated against racism and unethical practices in the discipline.