12. Personalized medicine a) can use a DNA microarray b) can be used to prevent adverse reactions to medicinal drugs C) can be used in the treatment of cancer d) all the above 13. Chromatin modifications: a) can be required in eukaryotes for gene expression b) can involve histone acetyltransferase enzymes (HAT) c) can relax the compact structure of chromatin d) all of the above 14. In vertebrate genes, focused promoters: a) are associated with genes th at are regulated start transcription at several specific base pairs that are near each other. c) are rare or absent d) all the above