All of the following devices transmit energy/information: cell phones, walkie talkies, remote controls, and sunlight.

Question

Which statement is true regarding these transmissions?
Responses
A They are all radiation.They are all radiation.
B They are all invisible.They are all invisible.
C They are all pressure waves.They are all pressure waves.
D They all travel at different speeds.

Answer 1

D They all travel at different speeds.