An organic methyl molecule attached to part of a DNA strand has been identified as a(n)

A) genome.
B) double helix.
C) epigenetic mark.
D) self-regulating gene.

An organic methyl molecule attached to part of a DNA strand is an example of an epigenetic mark. Epigenetic marks are changes to the DNA molecule that do not involve changes to the underlying genetic code, but which can still have significant effects on gene expression and cellular function. Methylation is a common epigenetic modification that involves the addition of a methyl group to one of the nucleotide bases in DNA, usually cytosine. Methylation can affect gene expression by altering the structure of the DNA molecule and making certain genes more or less accessible to the cellular machinery responsible for reading and transcribing genetic information.