Plz with all of them! read instructions. i will give you 30 points. no joke.

The coolant gas in a fridge takes heat from the fridge and "pumps" or "dumps" it in the outside. The back of a working fridge is usually quite warm, and one source of that heat is the contents of the fridge.
Electrical energy is used to pump the coolant round the various components of the fridge's cooling system. It also possibly powers any lights in the fridge. That funny whirring sound may well be a motor, and motors are driven by electrical energy. If your power goes off, then your fridge stops fridging. all the stuff in the fridge warms up to room temp slowly, and you may end up with some "too warm" grub.