Is every disturbance fundamentally a combination of harmonics

I started this by thinking of this: Is audio fundamentally comprised of frequencies

• Even considering electromagnetic waves, is it correct for us to consider that every disturbance or sound can be modeled as a combination of harmonics?
• Sure, it is possible, and mathematically valid; however, is it fundamental?
• I think that vibrations are the natural state of an undisturbed field, however, the fields in our universe are not undisturbed.
• That's not to say there can't be an undisturbed universe.
• I think any alive universe should have a prime mover configuration.
• Should the universe have a prime mover (moved to it's own page)