Select all the examples of evidence for nucleosome supercoiling. A. A 300 Å fiber with 6 nucleosomes per turn is visible using electron microscopy.
B. Removal of some histone H1 causes the 300 A to unwind to 100 A.
C. Using electron microscopy, nucleosomes appear like beads with a diameter of 100 Å.
D. Metaphase chromosomes from which histones have been extracted still maintain an X-like shape.
E. Loops of chromatin are visible using electron microscopy.

A. A 300 Å fiber with 6 nucleosomes per turn is visible using electron microscopy.

C. Using electron microscopy, nucleosomes appear like beads with a diameter of 100 Å.

E. Loops of chromatin are visible using electron microscopy.

Explanation:

The nucleosomes are the key subunits of the chromatin, and they consist of two turns of DNA wrapped around a set of two copies each of the H2A, H2B, H3, and H4 histone proteins (i.e. an octamer of histones), which are connected by linear DNA and H1 histones. A zig-zag array of the nucleosomes form a 100 Angstrom (10-nm) nucleosome fiber. Subsequently, multiple histones are packaged into a 30-nanometer (300 Angstrom) fiber named solenoid. The chromatin loops are finally condensed into higher-order structures, which form chromosome sections (300 nm) and chromosome arms (700 nm), respectively.

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.