Do electromagnetic waves need molecules to travel?

Idon't understand is there supposed to be a list or something if there is pm or add in under this message i will do my best to .

The correct option is this: the sound waves from the two trombones have slightly different frequencies.from the question given above, we are told that the loudness of the sounds were increasing and decreasing, this is because the frequencies of the two sounds are different. the means that the number of waves that pass a fixed point in a given amount of time differ for both sounds.

Ais