which is true about the characteristics of sound?
A. Sound could either be soft or loud
B. The loudness of sound decreases as it moves nearer the observer
C. Sound is not heard when it is exactly on the same spot as the listener
D. The loudness of sound increases as it moves away from the observer

Which of the following is good to use when we go out on a sunny day?
A. Umbrella
B. sunglasses
C. sunblock
D. All of these

Which of the following is good to use to protect our ears from the noise in the environment?
A. Ear muffs
B. cotton buds
C. earrings
D. All of these​