What is a gluon?

A gluon is a fundamental particle that acts as the exchange particle for the strong force, which is one of the four fundamental forces in nature. It is responsible for holding quarks together to form protons and neutrons, which in turn make up an atom's nucleus. Gluons are a type of boson, and their role is crucial in the field of quantum chromodynamics (QCD), which describes the interactions between quarks and gluons.

In the context of the other options, an electron is a distinct type of fundamental particle, belonging to the lepton family, and is not related to the strong force. Protons and neutrons are composite particles made up of quarks, held together by gluons, making them fundamentally different from gluons themselves. Understanding gluons is essential for grasping the interactions that govern the behavior of matter at the subatomic level.