Hi, I think you forgot to list the characteristics.
Answer:
The amount of energy in a sound wave is called
Volume
D
I answered C and it was marked wrong
Answer:
B. Surface of the skin
Explanation:
If we had mucous on the surface of our skin then our skin would have a thick slippery fluid like substance on it all of the time. Mucuos membranes are present in the digestive tract, mouth, lungs, and more.