Options:
a) A different kind of rock
b) An underground lake
c) An open cavity
d) A pile of dinosaur bones
Answer:
Option B. An underground lake
Step-by-step explanation:
The speed of sound in water ranges from 1450 m/s to 1500 m/s. The speed of the sound wave changes because it has crosses two media of different densities. This wave is bound to have a change in direction because of change in the density and speed of the media it passes.
The 1500 m/s speed in the second medium shows that the medium is a pool of water. The only option that applies is an underground lake