Answer:
For the first one, its B) cities B and C
I'm not so sure, but I hope this helps.
Answer:
Hey Krista: Burning is a type of chemical change using fire and heat that produces new substances "Buming"* things like wood or bread changes their color and odor
This is the best discription because it describes what things can burn and what happens to them.
*i don't know what "buming" means but i think you mean burning, lol.
Answer:
|Δf| = 37.3 kHz
Explanation:
given,
peak velocity = 4 m/s
speed of the sound = 1500 m/s
frequency = 7 MHz




= 37.3 kHz
|Δf| = 37.3 kHz
hence, frequency shift between the opening and closing valve is 37.3 kHz