:new research is revealing that many cancers involve epigenetic alterations of: the bases a and t coding sequences in the dna oncogenes histones, the proteins around which dna is wrapped

While genetics corresponds to the study of genes, epigenetics is interested in a "layer" of complementary information that defines how these genes will be used by a cell ... or not.

In other words, epigenetics is the study of changes in gene activity, does not involve modification of the DNA sequence and can be transmitted during cell divisions. Unlike mutations that affect the DNA sequence, epigenetic changes are made on the proteins surrounding the DNA and are reversible.

So the right answer is the proteins around which dna is wrapped

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.

looks like the answer is     c     to me!