Final answer:
One shared characteristic of ethnic groups is C. unique cultural traits, such as language and clothing, which form the basis of their shared culture and identity. The correct option is (C).
Step-by-step explanation:
One of the characteristics shared by ethnic groups is C. unique cultural traits, such as language and clothing. Ethnicity is based on shared culture which includes practices, norms, values, and beliefs.
These distinctive cultural aspects often encompass a shared language, religion, customs, and traditions defining a group's identity.
Members of an ethnic group may identify or self-identify with these traits in various ways, and these identifications play a role in shaping how individuals and institutions categorize and interact with different ethnicities.
It is also important to note that members of national identity groups may share some of these characteristics and seek recognition or autonomy to protect their linguistic, religious, and cultural traditions.
Moreover, communities sharing an ethnicity often provide mutual support to one another and can experience fewer conflicts due to common values and traditions.