Given that an estimated five trillion hydrogen atoms can fit on the head of a pin, and each of those hydrogen atoms has four particles (one electron, and three quarks in the proton), we can safely assume that the number of particles in the entire observable universe is, well, pretty much beyond comprehension.
There are six types (or flavors) of quarks: up, down, charm, strange, top, and bottom (see infobox above, "Generations of matter"). .... after the Big Bang, when the universe was in an extremely hot and dense phase (the quark epoch).
Why are there only six?
Why not 1 or 20?