You are presented with the question "What are used for communication by two people by transmitting waves?" and the following answer choices: 
- satellites
 - A Greek letter
 - Morse code
 - mitosis
 - telephones
 - energy
 - electricity
 - photosynthesis

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


 

     telephones    