Anthropologists have studied the role of soybean curd and its related by-products in the culture of Hong Kong. The researchers interviewed people about how frequently they ate soybean products, where they ate them (at home or in restaurants), and during what time of day they ate them. The researchers also asked people about how they prepare soybean products, where they obtain soybean products, and any beliefs they might have about the soybean products (such as their nutritional value). The data were used to assess the role of soybean products in the culture. The researchers also considered how this relates to global soybean consumption patterns. What is the primary field of anthropology addressed in this research?

Biological anthropology is demonstrated as the domain of anthropology that focuses on the evolution of humans or how they have evolved in their behavior as well as biological aspects and their bio-social difference.

As per the given description, the given research exemplify 'biological anthropology' as it primarily emphasizes an evolutionary point of view and studies the part played by 'soybean curd and its related by-products in the culture of Hong Kong'. It also focuses on the biological variation('how frequently they eat Soybean and where') and adaptation(how they prepare or or consumption patterns or beliefs associated to it ').

Thus, the prime focus of this research is to assess that humans have evolved biologically to adapt themselves to the diverse/varied environments(reflected by their eating pattern of Soybean and its role in their life) and how their behavior(influenced by the beliefs) and culture have been shaped by these changes.