What does ultrasound refer to?
Choose only ONE best answer.
A
Sound waves below 20 kHz
B
Sound waves above 20 kHz
C
Sound waves below 10 kHz
B
Sound waves above 20 kHz
Choose only ONE best answer.
A
Sound waves below 20 kHz
B
Sound waves above 20 kHz
C
Sound waves below 10 kHz
Sound waves above 20 kHz