G. what happens if a homologous pair of chromosomes fails to separate, and how might this contribute to genetic disorders such as down syndrome and cri du chat syndrome?

Cri du chat syndrome is caused by a partial deletion of chromosome 5p. Down syndrome is a result of an extra copy of chromosome 21. Non-disjunction occurs and the result is that one gamete has 2 copies of one chromosome and the other has no copies of that chromosome.