Fact 1: Telephones are used for communication by two people by transmitting sound.

Fact 2: Additionally, sound can be transmitted with video.

Given the two facts above, answer the question "What technological tool can be used for communication?" with the following options: 
- electricity
 - satellites
 - biotechnology
 - telescope
 - animals
 - radiography
 - telephones
 - laser


 

       telephones  