Asymmetric cell division
In C. elegans the three principal axes of the body (Anterio/Posterior, Dorsal/Ventral, and Left/Right) are established by a series of asymmetric cell division. It's through these types of division that cell determinants are unequally segregated into daughter cells resulting in the specification of cell fates. The first cell division in C. elegans, in the one-cell embryo, results in the establishment of the A/P axis.