how can i distinguish motors?

have a 1991 prelude si coupe......no idea if its the 2.0 or 2.1.....anyone know how i can distinguish between the 2? also, which one is better or are they both old and junk? dont know hardly anything about hondas....thanks

Its a 2.1 Look for the code to the left of the exhaust manifold on a little square the sticks out.