(N/A) To demonstrate that the same current flows through every part of a series circuit,follow these steps:
$1$. Connect three resistors $(R_1, R_2, R_3)$ in series with a battery,an ammeter,and a plug key.
$2$. Place the ammeter at different positions in the circuit: first between the battery and the first resistor,then between the resistors,and finally after the last resistor.
$3$. Observe the reading of the ammeter in each position.
$4$. You will notice that the ammeter shows the same reading in all positions.
$5$. Conclusion: Since the ammeter measures the current flowing through the circuit,the identical readings confirm that the same amount of current flows through every component in a series circuit.