Complete the following sentences —

(a) An average person can hear sounds of frequencies in the range ………. to ……….

(b) Ultrasound is of frequency ……….

(c) Infrasonic sound is of frequency ……….

(d) Bats can produce and hear ………. sound.

(e) Elephants produce ………. sound.

(a) An average person can hear sound of frequencies in the range 20 Hz to 20 kHz.

(b) Ultrasound is of frequency above 20 kHz.

(c) Infrasonic sound is of frequency below 20 Hz.

(d) Bats can produce and hear ultrasonic sound.

(e) Elephants produce infrasonic sound.