Final answer:
For every two H4 histones, there is one nucleosome. Therefore, 200 copies of H4 would indicate the presence of 100 nucleosomes in the chromatin.
Step-by-step explanation:
If a piece of chromatin contained 200 copies of the histone H4, we must determine how many nucleosomes are present. Each nucleosome is an octamer consisting of two copies each of four histones: H2A, H2B, H3, and H4. Since H4 is mentioned, we can infer that for each H4 there is a complete set of histones making up a nucleosome.
To find the total number of nucleosomes, we take the total number of H4 histones and divide it by the number of H4 histones in each nucleosome. Given that there are two H4 histones in each nucleosome, dividing 200 by 2 yields 100 nucleosomes. Therefore, if there are 200 copies of H4, then there would be 100 nucleosomes in that piece of chromatin.