Telephones are used for communication by two people by transmitting sound.
Loudspeakers then turn the signals into sounds.
Telephones are used for communication by two people by transmitting signals.
What are used for communication by two people by transmitting signals?
Options:
(A) electricity
(B) satellites
(C) air
(D) phytoplanktons
(E) unidirectional
(F) telephones
(G) the Sun
(H) waves