Nucleosomes give chromosomes a beaded appearance. They help in the packaging of $DNA$ in chromosomes. $A$ nucleosome consists of:

• A
  It has $2$ turns of $DNA$ wrapped around it.
• B
  Eight histone molecules of four types ($H_2A, H_2B, H_3$ and $H_4$,$2$ molecules of each).
• C
  $200$ base pairs of $DNA$.
• D
  All of the above.