The difference between extrusive and intrusive rocks are how they cool
down. Extrusive rocks cool down quickly and are created by lava; because
of this they have very small, fine-grained crystals. Intrusive rocks
cool slowly beneath the surface of the earth and are created by magma;
because the cooling process is very slow the rocks have very large
crystals.
What I know is that amino acid has side chain, amine groupe ,and groupe of carboxyl so what make them difference is side group where the is 20 different R-group which give each individual characteristics
