Question

fill in the blank question
at the beginning of mitosis, the two chromatids of each duplicated chromosome are joined together at a central region called the blank.

Explanation:

In mitosis, duplicated chromosomes have two sister chromatids. These chromatids are joined at a region known as the centromere. This is a key concept in cell biology (a subfield of Biology, which is part of Natural Science) related to chromosome structure during cell division.

Answer:

centromere