Answer:
D.Mechanical waves always require a medium to travel.
Explanation:
Longitudinal waves: It is that type of waves in which waves require a medium to travel.Longitudinal waves can be modeled by spring. Example: mechanical waves.
Transverse waves:It is that type of waves which may or may not require medium to travel depending upon the type of wave.Example:EM and ocean waves.
A.It is false because EM waves are always transverse waves.
B.It is false because mechanical waves are always longitudinal waves.
C.It is false because EM waves always do not require a medium to travel.
D.It is true because mechanical waves are longitudinal waves which require a medium to travel.
Answer:D.Mechanical waves always require a medium to travel.
