The correct answer is telephone.
Telephone arose from an attempt to help hearing-impaired people.
Telephone is termed as a telecommunication which allows either two or more users to have a conversation while they are apart and to be heard directly.
Telephone converts human voice or sound to electronic signals which are being transmitted through cables.
Some of the elements which are essential in telephone are earphone which are termed as receiver and microphone which is the transmitter.
Most of the telephone they have a ringer which produces a sound to show that there is an incoming call.
It helps control the sugar in the body
