The speed at which the machine sews is controlled by the

foot pedal

bobbin
thread guide
needle

i think its the first one?

Are you supposed to guess? Or do you have choices to consider?

And you think it's ... ?

Have you ever used a sewing machine?

Right.

The speed at which a sewing machine sews is controlled by the foot pedal or a speed control button. However, it may vary depending on the specific make and model of the sewing machine.

To control the speed using the foot pedal, you need to connect it to the sewing machine. The foot pedal has a sensor that detects how much pressure you apply when using it. When you press the foot pedal lightly, the sewing machine stitches at a slow speed. On the other hand, pressing the foot pedal harder makes the sewing machine sew at a faster speed.

If your sewing machine has a speed control button, you can adjust the speed using this feature. This button allows you to choose the desired speed by selecting a lower or higher setting, typically measured in stitches per minute (SPM) or in percentages. By pressing the lower setting, the machine will sew at a slower speed, while pressing the higher setting will make it sew at a faster speed.

In summary, the speed of a sewing machine is controlled either by the foot pedal, where the pressure you apply determines the speed, or by using a speed control button that allows you to adjust the speed settings directly.