Explanation:

- Student Union

- A student union is a group formed in a school or university to represent the interests and activities of students.

- This can be considered a community as it involves people with common interests and goals.

- Tribe

- A tribe is a social group that shares a common ancestry, culture, language, or tradition.

- This is definitely a community due to its shared characteristics and social bonds.

- Family

- A family consists of individuals related by blood or marriage, sharing emotional connections and responsibilities.

- This is a community as it involves shared connections and support systems.

- Crowd

- A crowd is a temporary gathering of people, usually without lasting bonds.

- ?? This typically isn't considered a community, as it lacks ongoing interactions or common goals.

Therefore, all options except for Crowd can be considered communities.