He is the main organizer of this event.

The meristem of this plant is very active.

Changes in the social system inevitably occur with time.

Social justice means that all people are treated equally.

He is an expert in sociology.

Actions that go against social norms are not allowed.

We should think deeply about the reform of the social security system.

He used to be a member of the Chinese gang.

He experienced the harsh reality of the underbelly of society.

His sociability is an important factor for his success as a leader.