6. The transient covalent modification of the N-terminal tails of the core histone proteins: (A) facilitates the process of transcription and DNA replication (B) disrupts nucleosome/DNA interaction by the introduction of a net positive charge on the nucleosomes. (C) is specific for the R groups of valine, isoleucine and alanine. (D) exclusively involve the histone tails of H2A and H2B. (E) answers A and B are correct