You are presented with the question "Telephones are used for communication by two people by transmitting what? " and the following answer choices: 
- Transmitting illness.
 - chemical messengers
 - encoded information
 - electromagnetic energy
 - Television.
 - Communication degree.
 - Mechanical waves.
 - Electrical energy

Now knowing that telephones are used for communication by two people by transmitting sound and sound Sound waves are mechanical waves, choose the best answer.


 

       Mechanical waves.  