How does histone modification silence transcription? check all that apply. a-histone demethylase demethylates the histone tail, which can increase heterochromatin. b-histone demethylase demethylates the histone tail, which can increase euchromatin. c-histone methyltransferase methylates the histone tail, which can increase euchromatin. d-histone methyltransferase methylates the histone tail, which can increase heterochromatin.

The correct answer will be option- A.

Explanation:.

Histone demethylases are the enzymes which controls the gene expression of any gene. These enzymes play an important role in epigenetic control of gene. The post-translational modifications like methylation and acetylation changes the structure of the chromatin which alters the interactions of the chromatin.

The histone demethylase removes the methyl group from the histone tails which causes the condensation of the loose chromatin structure to form heterochromatin.

Thus, option-A is the correct answer.

a) carbon, hydrogen

b) carbon, hydrogen, oxygen, nitrogen

c) carbon, hydrogen, oxygen, nitrogen, phosphorus

d) sugar

e) amino acid

f) nucleotide