Electrons of the current in a circuit?

I have a traditional circuit (a conductor wire, and voltage source and a resistor). The voltage source may be a battery in this case.

My questions(s) are:

• From where do the electrons that flow in the circuit come from? Do they come from the wire or from the voltage source? I assume they come from the wire itself since the conductor has electrons in its last level that it can easily get rid of?


• Looking at voltage in primitive terms: Is it a kind of repelling power? For example, will a negative voltage source repel electrons in the conductor, thus causing a current? Is that correct?