Here's why:

* Resistance: Resistors have a property called resistance, which opposes the flow of electric current. The higher the resistance, the more it restricts the current.

* Ohm's Law: The relationship between current (I), voltage (V), and resistance (R) is described by Ohm's Law: I = V/R. This means that by changing the resistance, you directly influence the current flowing through a circuit.

Other devices that can control current:

* Variable Resistors (Potentiometers): These allow you to adjust the resistance manually, providing a range of current control.

* Transistors: These semiconductor devices act as electronically controlled switches or amplifiers, enabling you to control current flow based on a signal.

* Diodes: These allow current to flow in only one direction, effectively limiting current in a circuit.

* Fuses: These are safety devices that break the circuit when the current exceeds a certain limit, preventing damage.

The specific type of device used to control current depends on the application and the desired level of control.