Which of the following best describes how wireless telephones are able to receive and produce sound from one person to another?
A.
Electromagnetic waves are received and then vibrate a speaker which produces additional electromagnetic waves.
B.
Sound waves are received and then vibrate a speaker which produces electromagnetic waves.
C.
Sound waves are received and then vibrate a speaker which produces additional sound waves.
D.
Electromagnetic waves are received and then vibrate a speaker which produces sound waves.

D.

Electromagnetic waves are received and then vibrate a speaker which produces sound waves.

Explanation:

The telephone has a receiver-transducer component that can receive electromagnetic wave - radio waves spectrum- and transform them into electric energy. This electric energy is then transformed into sound energy by a speaker. This is how we're able to listen to a phone call.

The opposite happens when we speak on the phone. The sound energy is transformed into electric energy by a microphone – the reverse of a speaker.  The transducer now changes the electric energy into electromagnetic waves that travel through space to the recipient in the phone conversation.

the answer is:  

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