Final answer:
Aneuploidy is the presence of an abnormal number of chromosomes in a cell and is true for the definition provided. It can lead to conditions such as Down Syndrome, resulting from trisomy, where an individual has an extra chromosome.
Step-by-step explanation:
True. Aneuploidy refers to the condition of having an incorrect number of chromosomes for a species, such as having too many or too few chromosomes due to an error during cell division.
Aneuploidy occurs when there is a deviation from the normal chromosome number, which is called euploidy. In humans, being euploid means having 22 pairs of autosomes and one pair of sex chromosomes. An aneuploid condition can entail either a monosomy, where there is a loss of one chromosome, or a trisomy, where there is a gain of an extraneous chromosome. These errors typically arise from nondisjunction during meiosis.
For example, Down Syndrome is a result of an extra copy of chromosome 21, which is a kind of trisomy. The severity of aneuploidy varies, with some conditions leading to non-viable zygotes, while others, such as certain trisomies, may result in individuals who can survive with various physical and developmental challenges.