Fact 1: Atelephone is used for communication by humans over long distances.

Fact 2: Communicating is as much about listening as it is about talking.

Given the two facts above, answer the question "People can listen and talk to each other over long distances using what?" with the following options: 
- Neuron.
 - power
 - microscope
 - microphone
 - electricity
 - dictaphone
 - telephone
 - waves


 

       telephone  