Answer:
The property of the wave marked X is related to the source of the wave
Step-by-step explanation:
The source of of origin of waves
Electromagnetic wave are waves that consists of varying electric and magnetic field that vibrate perpendicular to each other and to the direction of propagation of the wave and they are therefore transverse waves and transfer energy
Electromagnetic waves originate from the vibration of charged particles that gives off varying electric and magnetic fields
Mechanical waves are defined as waves that require a material medium such as air, water, metal, plastic, stretched leather, or wood to propagate
Mechanical waves originate from vibration of the particles of a medium
Sound waves which is a form of longitudinal mechanical waves that propagates by the vibration of the particles of a given medium about a point parallel to the direction of propagation of the wave.