Answer:
Does the wave require a medium in order to travel?
Step-by-step explanation:
The question whose answer would determine whether the wave in question is mechanical or electromagnetic would be if the wave requires a medium in order to travel or otherwise.
A mechanical wave would require a medium in order to transport its energy from one place to another, that is, travel. On the other hand, an electromagnetic wave does not require any medium in order to travel, that is, it can travel through vacuums or empty spaces. Light and sound waves are typical examples of electromagnetic and mechanical waves respectively.