Why is dissipation of electric power as heat minimized? For a given electric circuit, currents and voltages are distributed to minimize the total power dissipated as heat. It seems that, there is some kind of action which is stationary.
What is the reason for this?
 A: Although your question is indeed unclear and also contains a statement which is not universally true lets try thinking about a few things;
The currents and voltages in a circuit are determined by the electrical properties of the parts of the circuit, primarily the supply voltage and the various resistances. It is always possible to calculate by equations, like Ohm's Law, what the voltages and current are in any place in the circuit. There is no magic distribution to minimise anything. Power dissipation occurs in all parts of the circuit and again it is possible to calculate it with formulae.
In the real world when designing electrical systems or circuits we may very well wish to minimise power dissipation in some parts. This is usually due to the fact that the heat is wasted, useless and may affect other things and, of course, costs money. In deciding on the design of such systems the choice of voltage and current may well be considered to keep unnecessary heat loses to an acceptably low level.
One example would be the design of a system to transmit 200MW of power from a power station to a town 50km away. Choosing a higher voltage for the transmission cables would result in lower current and hence lower heat loss in the cable all other things being equal.
If however I am designing an electric storage heater I would be wanting to maximise the heat produced by the electric current !
