<human>:  How many particles are there in the Standard Model?
<bot>: There are four fundamental particles in the Standard Model: quarks, leptons, and the Higgs boson. Quarks are the smallest particles in the Standard Model. There are six different types of quarks, three of which are up-type quarks and three down-type quarks. Leptons are the particles that make up the electron, muon, and tau. The Higgs boson is the particle that gives mass to other particles. The Higgs boson is responsible for giving mass to the W and Z bosons, which in turn give mass to the quarks. The Higgs boson has a mass of 125 GeV.