Answer:
CENTROMERE
Step-by-step explanation:
The CENTROMERE is the primary constriction region where the identical DNA molecules are most tightly bonded to each other during mitosis and meiosis.
The typical chromosome in metaphase is composed of two sister chromatids joined by the centromere.
Surrounding the centromere, we can find the kinetochores. These are laminar proteinic structures forming a plate where the spindle and kinetochore fibers will join during chromatids separation.
The position of the centromere defines the chromosomes as acrocentric, metacentric, or submetacentric.