Dolphins communicate using compression waves. Some of these sounds are outside the range of human hearing. Upon spotting a hungry shark, dolphin A sends a message to dolphin B. To send this message as quickly as possible, dolphin A would

No because a circle or pie graph usually shows percentages you'd need a line graph

I'll do it rn and then answer

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.