17. Which one of the statements about heterochromatin is NOT CORRECT? (A) It is often tightly packed form of DNA (B) There are facultative heterochromatin and constitutive heterochromatin and both play a role in the expression of genes (C) Heterchromatin has been associated with the di- and tri-methylation of H3K19 in certain portions of the genome (D) Euchromatin and heterochromatin could be distinguished cytologically by how intensively they are stained, and typically heterochromatin stains intensely while euchromatin is less intense (E) Heterochromatin consists mainly of genetically inactive satellite sequences