# Why is usual matter made up of $n,p$ and $e^-$?

We have six leptons and six quarks. Yet most of what we see around us is made of only neutrons, protons and electrons. For $$\mu^-$$ and $$\tau^-$$, I think the reason is that these are unstable particles and quickly decays into $$e^-$$. But I have the following doubts.

1. Why do neutrinos, $$\nu_e,\nu_\mu$$ and $$\nu_\tau$$ do not form ordinary matter?

2. We do know about certain baryons and mesons containing $$s$$ quark in addition to $$u$$ and $$d$$. Are they all unstable? Why?

3. Is any bound state containing $$c,b$$ or $$t$$ quark unstable?

2. Yes. The standard reference website with the most up-to-date information is http://pdglive.lbl.gov/. You can look there at the lifetimes of the $$\Lambda$$ and $$\Sigma$$ baryons and check for yourself that they are very small.