It is my understanding that subdominant chords, IV and ii, contain the fourth scale degree. The fourth scale degree wants to resolve down to the third scale degree. In the scale of C major (C, D, E, F, G, A, B, C), the F note wants to resolve down to E.
1) What makes a note want to resolve?
If it is because it is a half step away, (even then, I still don't understand why that makes it want to resolve), how come in a minor scale, the iv and iio scale degrees also have this tendency? In a C minor scale, (C, D, Eb, F, G, Ab, Bb, C) the fourth scale degree is now a whole step away from the third scale degree, not a half step anymore. What makes F want to resolve down to Eb?
By the same token, in C major scale, B wants to resolve up to C (half step). In this case why does Bb want to resolve up to C (whole step)?