The bead of each nucleosome core contains which combination of histone molecules?

Correct answer: Two copies each of H2A, H2B, H3, and H4.

Explanation

The fundamental repeating unit of chromatin is the nucleosome, which consists of a histone octamer core (two each of H2A, H2B, H3, H4) with DNA wrapped around it, and a linker segment bound by histone H1.