Fill in the Blank in the Following Paragraph Regarding Chromatin

Short Answer

Fill in the blank in the following paragraph regarding chromatin organization. Do not use abbreviations.
"Our ~6.4-giganucleotide nuclear DNA is organized into 46 chromosomes, each occupying a territory inside the interphase nucleus. In each chromosome, the chromatin is thought to be composed of 'open' and 'closed' chromatin compartments. At the meganucleotide scale, each compartment is organized into knot-free arrangements called … that allow tight packing and simultaneously avoid entanglement."