Notice that both quarks and leptons exist in 3 distinct sets.
We call each of these sets a generation of matter particles. A
generation is a set of one of each charge type of quark and lepton. Each generation tends
to be heavier than the previous set.
All visible matter in the universe is made from
the first generation of matter particles: up and down
quarks, and electrons. Second and third generation particles are
unstable, and decay into first generation particles. It is for this reason that all the
stable matter in the universe is made from first generation particles.