During oogenesis in an animal species with a haploid number of 6, one dyad undergoes nondisjunction during meiosis II. Following the second meiotic division, this dyad ends up intact in the ovum. How many chromosomes are present in (a) the mature ovum and (b) the second polar body? (c) Following fertilization by

a) 3 cromosomes b) 3

Explanation:

The haploid number of a cromosome is the total number ofcromosomes withoutits homologue partner. In this case, if the text indicates that the haploid number of cromosomes is 6, then that is the total number of cromosomes in the result cell.

The ovum contains just half of the information that will be given in order to form the new organisms, in this context, if the result organism has cromosomes, the ovum will only contain 3.

In meiosis II, after both cigotes get together and unite all the 6 cromosomes, it separates again. This means that the second polar body will remain will only 3 cromosomes again.