A bus is a kind of motor vehicle [kinds of vehicles].
A tire is a part of a car [parts of cars].
Cheating is a way to get high grades in school [ways students get high grades].
A train is used for transporting goods [ways to transport goods].
High unemployment is a reason for public unrest [reasons for public unrest].
The charge is a stage of a battle [stages of battle].
A coal power plant is a cause of acid rain [causes of acid rain].
A town square is a place for a mob to gather [places where mobs gather].
Wearing spiked, colored hair is a characteristic of punks [characteristics of punks].