How many types of quarks are there in the standard model of physics?

In the standard model of physics, there are six types of quarks, namely up, down, charm, strange, top, and bottom. Each type of quark differs in their mass, charge, and other properties. These quarks combine with each other to form composite particles, such as protons and neutrons, which are the building blocks of ordinary matter. The number six arises from the observation that there are three generations of quarks, with each generation consisting of two quarks. The existence of these six quarks is supported by various experimental evidence and is a fundamental part of the standard model, which describes the fundamental particles and the forces that govern their interactions.