Yes, hadrons are composite particles that are made up of quarks. Quarks are fundamental particles that have fractional electric charges (-1/3 or +2/3 times the elementary charge) and are governed by the strong nuclear force, which is mediated by particles called gluons.
Hadrons are classified into two main categories: baryons and mesons. Baryons are composed of three quarks, while mesons are made up of a quark-antiquark pair. Protons and neutrons, which are the building blocks of atomic nuclei, are examples of baryons. Protons consist of two up quarks and one down quark, while neutrons consist of one up quark and two down quarks.
The combination of different types of quarks and their respective properties determines the various characteristics of hadrons, such as their mass, charge, and other quantum numbers. The strong force binds the quarks together within the hadrons, and this interaction is described by the theory of quantum chromodynamics (QCD), which is part of the standard model of particle physics.
It is worth mentioning that the concept of quarks and their role in forming hadrons has been supported by numerous experimental observations and theoretical studies.