What term describes a group of individuals with a unique identity based on shared traditions and customs?

The term that best describes a group of individuals with a unique identity based on shared traditions and customs is "ethnic group." An ethnic group is characterized by shared cultural traits, including language, religion, and customs that contribute to a collective identity among its members. These groups often have a common historical background or ancestry that shapes their cultural practices and social dynamics.

In contrast, other terms like cultural diversity refer to the presence of multiple cultural or ethnic groups within a society, highlighting a broader array of identities rather than focusing on a single group's unique identity. A subculture is a group that exists within a larger culture but maintains distinct traits, often based on specific interests or lifestyles, rather than solely on shared traditions. Lastly, the term social group is more general and can encompass any grouping of individuals based on any criteria, including geography, social class, or common interests, rather than specifically shared culture or ethnic identity. Therefore, "ethnic group" accurately captures the concept of shared identity through traditions and customs.