Answer:
Music in movies help set the mood of the scene. For example if something big is about o happen the music in the background will build up till that moment. Or if they're trying to get a reaction from the audience, they'll use a loud jump in the quiet music to startle the audience, much like in horror or thriller movies. The music helps the audience know the mood of the current situation of the scene or what to expect or make them expect.
Explanation:
I'm not too good at explaining things, I hope this helps :)
