What are the primary and secondary constrictions of a chromosome? What is the other name given to the secondary constriction?

Answer 1

1. primary constriction is the chromosome region where the centromere is (chromosomes can only bend at primary constriction site)
2. secondary constriction is the narrow chromosome region found at any region other than the centromere
3. secondary constriction is also known as nucleolar organizer or "nucleolar organizing regions" (NORs)