The idea that everything around us, including ourselves, is made up of just three simple particles—namely, the electron, up quark, and down quark—is an oversimplification of the composition of matter. While these particles are indeed fundamental constituents of matter, the complete picture is more complex.
In the standard model of particle physics, which is the prevailing theory describing the fundamental particles and their interactions, there are several other types of quarks and leptons that make up matter. Quarks are the building blocks of protons and neutrons, which, along with electrons, form the atoms that constitute ordinary matter.
In addition to up and down quarks, there are two more types of quarks called charm and strange quarks, and two heavier quarks known as top and bottom (or top and bottom quarks). These quarks have different masses and properties but share certain characteristics, such as carrying fractional electric charges.
Similarly, besides electrons, there are two more types of charged leptons: the muon and the tau, each with increasing masses. Alongside the quarks and leptons, the standard model also incorporates force-carrying particles called gauge bosons, such as photons, W and Z bosons, and gluons, which mediate the electromagnetic, weak, and strong nuclear forces, respectively.
It's important to note that the standard model does not account for gravity, and the discovery of the Higgs boson in 2012 provides insight into the mechanism through which particles acquire mass. However, the standard model is considered incomplete as it does not encompass gravity and does not account for phenomena such as dark matter or dark energy.
So, while the electron, up quark, and down quark are indeed fundamental particles, our understanding of the composition of matter is more nuanced, involving a broader range of particles and their interactions.