69 is the answer because I know or it could be 430
Answer: Acoustics
Explanation:
Acoustics is simply refered to as a branch in physics that studies sound and its wave.
Acoustics studies mechanical waves in liquid, solid state or gaseous state. Topics such as infrasound, vibration and ultrasound are studied. Someone who works in the acoustics field is referred to as an acoustician.
Answer:
where are the step number. I can't find any