Final answer:
When producing a "z" sound, the vibration you feel is caused by the vocal cords vibrating. This sound is a voiced fricative.
Step-by-step explanation:
When you put your fingers on your throat and produce a "z" sound, you will feel a vibration. This vibration is caused by the vocal cords vibrating. The "z" sound is known as a voiced fricative, which means it is both voiced and produced by a narrow opening in the vocal tract.