Which of the following are features of nucleosomes? A nucleosome contains approximately 20 base pairs of DNA. The DNA in a nucleosome is wound around eight histone proteins. Between nucleosomes is a stretch of DNA called "linker DNA". A nucleosome contains 8 different types of histones. In a nucleosome, DNA is wrapped 4 times around the histone core. H1 seals off where DNA enters and leaves the nucleosome. Nucleosomes contribute to DNA packing. Nucleosomes in chromatin are arranged in straight, side-by-side chains. Nucleosomes are about 10000 Angstroms in diameter. Histones have tails that stick out and can be modified, affecting DNA expression.

The correct answers are "The DNA in a nucleosome is wound around eight histone proteins", "Between nucleosomes is a stretch of DNA called "linker DNA", "H1 seals off where DNA enters and leaves the nucleosome", "Nucleosomes contribute to DNA packing", and "Histones have tails that stick out and can be modified, affecting DNA expression".

Explanation:

Nucleosomes are comprised of DNA and histones that in conjunction form structural units of the chromosomes. The DNA in a nucleosome is wound around eight histone proteins, which are known as the histone octamer. Between nucleosomes is a stretch of DNA called "linker DNA", which is an unwrapped DNA that can be between 10 to 50 base pairs long. H1, one of the four types of histone, seals off where DNA enters and leaves the nucleosome serving as an anchor to the complex. Nucleosomes contribute to DNA packing by wrapping the DNA and forming the structural units of the chromosomes. Histones have tails that stick out and can be modified, affecting DNA expression; which are known as "histone tails" located in the N-terminal side and where higher order structures are arranged.