Female gametes (ova) are more likely (than male gametes) to have chromosomal abnormalities such as aneuploidies (where one or more chromosomes are either lacking or present in excess). What is the most likely reason for this?

a. Oocytes arrest in prophase I during fetal development and remain there until ovulation decades
later.
b. Developing oocytes are exposed to more fat soluble carcinogens.
c. Female germ cells are constantly replicating, starting at puberty.
d. Fluctuating hormone levels lead to chromosome nondisjunction in oocytes.
e. Chromosome non-disjunction leads to the form

Question

Female gametes (ova) are more likely (than male gametes) to have chromosomal abnormalities such as aneuploidies (where one or more chromosomes are either lacking or present in excess). What is the most likely reason for this?

a. Oocytes arrest in prophase I during fetal development and remain there until ovulation decades
later. 
b. Developing oocytes are exposed to more fat soluble carcinogens.
c. Female germ cells are constantly replicating, starting at puberty.
d. Fluctuating hormone levels lead to chromosome nondisjunction in oocytes.
e. Chromosome non-disjunction leads to the form

anonymous · Answer

Answer give in A. need explanation on that

anonymous · Answer

Hope this helps: Aneuploidy represents the greatest genetic affliction of humans. However, little is known about the causes and even less about the underlying molecular mechanisms of aneuploidy, especially in mammalian germ cells, where most aneuploidy is thought to arise. Human aneuploidy is linked with embryonic loss, mental and physical anomalies, and cancer. Approximately 10–30% of fertilized human eggs,1 10% of all human conceptuses,2,3 50% of spontaneous abortuses,4,5 and 0.31% (204/64887) of human newborns have an abnormal number of chromosomes. Even though numerous hypotheses have been proposed for the etiology of human aneuploidy, the only consistent findings are its positive correlation with maternal age, and its more frequent occurrence during female meiosis I for certain chromosomes. Although the relationship between human aneuploidy and maternal age remains elusive, data suggest that such an association is linked to decreased frequencies of chiasmata formation, abnormally placed chiasmata, progressive losses of cohesion proteins, and spindle checkpoint proteins. It is now generally accepted that both nondisjunction and premature centromere separation (PCS) represent major events leading to human germ cell aneuploidy, and that variation exists among chromosomes for the likelihood of missegregation. http://www.ndsu.edu/pubweb/~mcclean/plsc431/chromnumber/number2.htm