Choose the word that correctly fills the blank in the passage O controlled
There is an musical instrument that you can play without actually touching
it. It is called the theremin and is electronic. The theremin has a box with two
metal antennas. The wires send and receive electromagnetic waves.
Because they are in the air, the antennas can exchange waves. One wire
controls pitch. This way the musician can play with the position of a sound in a
wide range. Another wire controls volume by using the correct level of
loudness. One can just move his or her hands towards or away from the
antennas to play the theremin. The electric signals from the thermin are
amplified with a loudspeaker. So, the sounds can be heard by a lot of people
o correct
O aerial
O actual