Question

what is the part of the model inside the gray box called? (hint: there are two of these seen in this model)
a centromere
a chromatid
a chromosome
the dna

Explanation:

In cell - division, a replicated chromosome consists of two sister chromatids. The centromere is the region that holds them together. DNA is the genetic material within the chromosome. The part of the model described (with two seen) corresponds to a chromatid.

Answer:

B. A chromatid