Answer:
Back
Power port, USB port, Game port
Front
Power button, USB port, Audio outlet
Step-by-step explanation:
There are several components that can be found on the system unit.
In most (if not all) computer system units, you will find more component at the back side than the front side.
Some of the components that can be found at the back are:
Ports for peripherals such as the keyboard, mouse, monitor, USB ports, power port, etc.
Some of the components that can be found at the back are:
The power button, cd rom, audio usb ports, several audio outlets, video port, parallel ports, etc.
Note that there are more components on the system units. The listed ones are just a fraction of the whole components