Examples:
 
One could say: "A typical system is a thermostat-controlled heating system, because in systems a setpoint is aimed for".

One could say: "Society is a typical system because systems are different from an environment"..

It is not a matter of adequate formulations, but rather of illustration by means of examples. Different people will have different ideas. The point here is that everyone works with their own ideas. Each participant can compare all statements of the course with his examples and thus recognize where his examples still hit the point of the course and where obviously something else is being talked about.