Answer:
b. Mainly between the conserved histone folds and the phosphate backbone of the DNA helix.
Explanation:
Histones are proteinous substances that are present in the chromatin of eukaryotic organisms.
The histones help to package or group DNA molecules in eukaryotic organisms into a structure that we refer to as chromosomes.
The contacts between the DNA and the histones of the nucleosome occurs mainly between the conserved histone folds and the phosphate backbone of the DNA helix.
Real Depth is actual distance of an object beneath the surface, as would be measured by submerging a perfect ruler along with it. Apparent depth in a medium is the depth of an object in a denser medium as seen from the rarer medium. Its value is smaller than the real depth.
Echinoderms, they are among the most common invertebrate animals in the marine environment of virtually any part of the world, among them we can find species such as sea cucumber , salmon and cod fish, they have chamois cloth like outer layer, then we have the Crinoids, another example of marine species with feather, popularly they are called sea lilies and feathery stars, they have a solid calcite skeleton; they were so abundant in the paleozoic seas that their remains formed large limestone thicknesses.