Which subatomic particle is currently considered the most fundamental particle of matter?

The quark is currently considered the most fundamental particle of matter because it is one of the basic building blocks of protons and neutrons, which in turn make up the atomic nucleus. Quarks are elementary particles, meaning they are not composed of smaller particles and therefore represent the most fundamental level of matter as understood in particle physics today.

Quarks come in different types, known as "flavors," and they combine in groups to form protons and neutrons, which are particles found in the nuclei of atoms. This structure implies that quarks are a key component in the formation of matter itself, serving as the building blocks that define the properties of atomic structure.

On the other hand, electrons, protons, and neutrons, while essential components of atoms, are not considered fundamental in this context because protons and neutrons are made up of quarks. Electrons are part of a different category of elementary particles known as leptons but do not have a substructure like quarks. Thus, the distinction lies in the current understanding of particle physics, where quarks are recognized as the foundational elements that constitute matter at the most basic level.