Why are all particles of a particular type of elementary particle all exactly the same? What kind of a process causes a lot of identical elementary particles to appear? How can a infinitely dense, hot, and small piece of space become a system with finite bounds (on energy, number of particles etc.)? There has to be something extra, otherwise why isn't there a universe with [current number of protons on this universe]+n, where n is an arbitrary number? I'm not a physics person so I would appreciate plain language. Thanks!