Chromatin
A complex of DNA, histones and nonhistone chromosomal proteins which make up the chromosomes found in eukaryotic nuclei[1]. 145 bp of DNA is wound into a left-handed superhelix [2] around 8 histones with up to 80 bp linking to the next "bead on a string". Each of these repeating units is a nucleosome.
Chromatin is formed to strengthen the DNA and decrease it's volume in the cell, thus preventing damage.