How does the accelerator pedal of carburetor car control the accelerator?

There are connecting rods between the accelerator pedal and the accelerator, some are connected by hard iron pipes through several joints, and some are connected by soft steel wires. When you press the accelerator pedal, the throttle of the carburetor will open. When you keep pressing the pedal. The throttle opening is getting bigger and bigger. The amount of mixed gas entering the intake branch pipe is also increasing. The engine speed will also be higher and higher. On the contrary. The engine speed will decrease.