Bats and dolphins use a phenomenon called echo location to find prey, predators, or obstacles. Echo location is a process where these animals emit high-frequency sound waves and then listen for the echoes that bounce back from objects in their environment. By analyzing the time it takes for the echoes to return and the intensity and frequency of the echoes, bats and dolphins can determine the location, distance, and even the shape and texture of objects around them. This allows them to navigate, hunt for food, and avoid potential dangers. Option 1, refraction of sound, is not the correct answer as it refers to the bending of sound waves when they pass through different mediums. Option 2, formation of beats, and option 3, scattering of sound, are also unrelated to the phenomenon used by bats and dolphins.