What does a resistor do in a circuit?

If there is but one resistor in the circuit, it will limit the current flow according to E = I*R

If there are two resistors in series in the circuit, they will affect a voltage divider.

Though you haven't asked for it, the voltage drop across the 3 ohm resistor is E = I*R

I = 5 amps

R = 3 ohms

E = 5 * 3 = 15 Volts

And through the 2 ohm resistor, you get

I = 5 amps

R = 2 ohms

E = 2*5

E = 10 volts.

So the total is 10 v + 15 v = 25 volts

Each resistor then has a reading in voltage across it. That is called a voltage divider.

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One "resistor" like a light bulb is made to give light and also to limit the current.

probably not the "magnets"in the magnet, so to speak, are thought to be electrons orbiting in shells. vurrent loops two sides to the loop

it doesn't. it was imagined up in the middle ages.