Dolphins communicate using compression waves (longitudinal waves). some of the sounds dolphins make 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 effectively as possible, dolphin a would question 1 options: send the message above the water when it jumps because air is more dense than water, and the sound would be louder above the water. make a higher pitched signal because a higher pitch is a louder sound. send the message underwater because a more dense medium would make the sound travel faster. make a softer sound because the shark will not hear the softer signal.

send the message underwater because a more dense medium would make the sound travel faster.

Explanation:

Dolphins communicate using compression waves - longitudinal waves. Longitudinal waves requires a medium to travel. A longitudinal wave transfers energy by the vibration of medium particles in the direction of the wave motion. Compression are the regions where density of the medium is higher and rarefaction is a low density region.

A longitudinal wave travels faster in a denser medium. It has maximum speed in solid and minimum in gas. Thus, to transfer message quickly to dolphin B., dolphin A should send the message underwater and not in air. This is because water has higher density than air. Molecules collide more quickly in water than in air and it takes less time for signal to travel.