Differentiation of cells is not easily reversible because it involves
a) changes in the nucleotide sequence of genes within the genome.
b) changes in chromatin structure that make certain regions of the genome more accessible.
c) chemical modifications of histones and dna methylation.
d) frameshift mutations and inversions.
e) excision of some coding sequences.

you must remain stopped until the stop signal is retracted and the red lights are turned off. approaching traffic in the opposite roadway of a divided highway shall not be required to stop, even if the school bus has the stop-arm extended and the alternately flashing warning signal lamps on.

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

c is the answer. hope this