If all you start with are the fundamental building blocks of nature — the elementary particles of the Standard Model and the forces exchanged between them — you can assemble everything in all of existence with nothing more than those raw ingredients. That’s the most common approach to physics: the reductionist approach. Everything is simply the sum of its parts, and these simple building blocks, when combined together in the proper fashion, can come to build up absolutely everything that could ever exist within the Universe, with absolutely no exceptions.
In many ways, it’s difficult to argue with this type of description of reality. Humans are made out of cells, which are composed of molecules, which themselves are made of atoms, which in turn are made of fundamental subatomic particles: electrons, quarks, and gluons. In fact, everything we can directly observe or measure within our reality is made out of the particles of the Standard Model, and the expectation is that someday, science will reveal the fundamental cause behind dark matter and dark energy as well, which thus far are only indirectly observed.
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