Have you heard an ambulance, police car, or fire truck recently? did you notice that the pitch of the siren changed as it approached you and then again as it moved away? what concept explains this change or shift in sound waves? question 1 options: changes in speed doppler effect changes in air temperature archimedes' principle

A). Yes ! I have heard an ambulance, a police car, AND a fire truck recently.

B). Yes ! ! I did notice that the pitch of the siren changed as the vehicle passed me, changing from a state of approaching me to a state of withdrawing from me.
(Refers to the ambulance and the fire truck only. The police car's siren was not turned on, but I could hear its motor.)

C). The Doppler Effect is a concept that can explain this apparent change or shift in the pitch or frequency of sound waves.

The best description is: . nobody has any idea what q is.

  concave means having an outline or surface that curves inward like the interior of a circle or sphere. so the mirror curves inward.