Final answer:
Monosomy and trisomy are examples of aneuploidy, an abnormal chromosome number within a cell, such as Down syndrome, which is a type of trisomy.
Step-by-step explanation:
Monosomy and trisomy are examples of aneuploidy, which refers to an abnormal number of chromosomes within a cell. When an individual is euploid, they have the appropriate chromosome number for their species. Humans are typically euploid with 22 pairs of autosomes and one pair of sex chromosomes.
Aneuploidy includes conditions like monosomy, where a chromosome is missing, and trisomy, where there is an extra chromosome.
An example of trisomy is Down syndrome (Trisomy 21), caused by having three copies of chromosome 21. This genetic disorder results from a nondisjunction event during meiosis, more likely to occur in older women over the age of 36, leading to increased frequencies of giving birth to children with Down syndrome.