How can sound be defined?

Sound can be defined as mechanical energy that is transmitted by longitudinal pressure waves moving through a medium such as air, water, or solids. In this context, sound originates from vibrations that create fluctuations in pressure, allowing the waves to propagate. These longitudinal waves involve the oscillation of particles in the medium in the same direction as the wave travels, which is essential for sound transmission.

The correct choice highlights this fundamental principle of sound propagation through mechanical waves, differentiating it from other forms of energy. Understanding sound in this way is vital when considering applications within aeromedical practice, where sound plays a crucial role in communication, diagnostics, and monitoring.