Question

the table above shows five different types of chromosomal abnormalities that can occur during meiosis. they result in either an individual having too many or too few chromosomes in their genome. what is the most likely cause of these chromosomal abnormalities?
a deletion of chromosomes
b insertion of chromosomes
c translocation of chromosomes
d nondisjunction of chromosomes

Explanation:

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (meiosis). This can lead to gametes with an abnormal number of chromosomes. For example, in Down Syndrome (Trisomy 21), there is an extra copy of chromosome 21. This extra chromosome is due to nondisjunction during meiosis in either parent. Similarly, Klinefelter's Syndrome (extra X sex chromosome) and Turner Syndrome (only one X sex chromosome) are also caused by nondisjunction of sex chromosomes during meiosis. Deletion (loss of a chromosome segment), insertion (addition of a chromosome segment), and translocation (exchange of chromosome segments between non - homologous chromosomes) are structural chromosome abnormalities, not related to the change in the number of chromosomes (aneuploidy) seen in the given syndromes.

Answer:

D. nondisjunction of chromosomes