Question

The most common extra chromosome condition that results in a surviving child is

A) Down Syndrome
B) Turner Syndrome
C) Klinefelter Syndrome
D) Edwards Syndrome

Answer 1

The most common extra chromosome condition resulting in a surviving child is Down Syndrome, where a baby receives an extra chromosome 21, leading to developmental and physical differences.

Step-by-step explanation:

The most common extra chromosome condition that results in a surviving child is Down Syndrome (Trisomy 21). This occurs when a baby receives an extra chromosome 21 from one of the parents, leading to a total of 47 chromosomes. Children with Down Syndrome often have some degree of mental and physical impairments, specific facial features, and they can live into adulthood. The occurrence of Down Syndrome is associated with chromosomal nondisjunction during meiosis, which becomes more frequent as maternal age increases. Other chromosome conditions like Turner Syndrome (monosomy X), Klinefelter Syndrome (XXY genotype), and Edwards Syndrome (Trisomy 18) are less common compared to Down Syndrome.