Adog whistle has a higher frequency than humans can hear, but dogs can hear it because they can hear sounds with higher than humans.
a. pitch
b. speed
c. altitude
d. amplitude

A. pitch
It can also be higher frequency

Ifound this on google “your outer ear collects sound waves and reflects them into a tiny tube called the ear canal. at the end of the ear canal is a thin, skin-like membrane stretched tightly over the opening, called the eardrum.” i hope this you for what your looking for