  We sketch an approximate method to quantify the number of correlated pairs in
any nucleus $A$. It is based on counting independent-particle model (IPM)
nucleon-nucleon pairs in a relative $S$-state with no radial excitation. We
show that IPM pairs with those quantum numbers are most prone to short-range
correlations and are at the origin of the high-momentum tail of the nuclear
momentum distributions. Our method allows to compute the $a_2$ ratios extracted
from inclusive electron scattering. Furthermore, our results reproduce the
observed linear correlation between the number of correlated pairs and the
magnitude of the EMC effect. We show that the width of the pair center-of-mass
distribution in exclusive two-nucleon knockout yields information on the
quantum numbers of the pairs.
