project due tommorrow plz help!!!<--------- hello, i am doing a project on the standard model for my school, i have two questions, 1)mesons are made of a quark and an anitquark, why dont they annihalate each other? 2)what is residual strong force all about, if each proton and neutron are colour neutral then why does the nucleus stick together? 3)also what are neutrinos, and i mean all of them tau electron and muon, and what do they do and how are they made 4)what is the point in spin? i have read many websites about this but none of them explain how different spins make different particles act towards each other.