Question

Consider the following statements regarding cellular differentiation:
(I) Differential gene expression, rather than gene loss, is the primary basis of cellular differentiation in multicellular organisms.
(II) Cytoplasmic determinants and positional signals play a role in directing cell fate during early development.
(III) Once differentiated, all cells irreversibly lose the ability to change their fate under any condition.
(IV) Epigenetic modifications such as DNA methylation and histone modification contribute to the maintenance of differentiated states.
Which combination of the above statements is correct?