Comfort and Convenience
Power mirrors adjust the glass by motor from a switch near the driver, so the rear view can be corrected while seated. They set the angle only; clearing mist or ice from that glass is a separate heating function.
Safety and Driver Assistance
The driver's airbag inflates from the steering wheel hub when a crash sensor registers deceleration severe enough to fire it. Its purpose is to cushion the head and chest against the wheel, working with the belt rather than replacing it.
Multimedia and Connectivity
The audio system is what turns a signal into sound through the speakers. A Bluetooth, USB or AUX link simply carries the material to it, so the connection decides the source while the system decides the playback.