Down syndrome
A) risk of occurring increases with the mother's age.
B) affects boys more than girls.
C) individuals rarely live past 5 years old.
D) individuals have normal organ and bone development but are mentally impaired.
E) disorder in related to a monosomy of chromosome 21.

Question

Quizplus · Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21, also known as trisomy 21. The risk of this extra copy occurring increases with the mother's age, especially above the age of 35.

Answer: D
 Individuals with Down syndrome have normal organ and bone development but are mentally impaired to varying degrees. They may also have characteristic physical features such as a flattened facial profile and an upward slant to the eyes.

Answer: Not B, Not C, Not E
 Down syndrome affects both boys and girls equally, and individuals with Down syndrome can live into adulthood with proper medical care. Down syndrome is caused by an extra copy of chromosome 21, not a monosomy.

Down Syndrome