Which of the following is true of Down syndrome?
A) The most common form of the disorder is also known as trisomy 21.
B) Trisomy 21 is an inherited disorder.
C) It is due to disjunction.
D) It cannot occur due to problems in mitosis.

Question

Quizplus · Accepted Answer

The most common form of Down syndrome is trisomy 21, where a person has three copies of chromosome 21 instead of the usual two.

Answer: C 
 Down syndrome is due to a chromosomal abnormality caused by the failure of the 21st chromosome pair to separate properly during meiosis, a process known as non-disjunction.

Answer: D 
 Down syndrome can occur due to problems in meiosis, but not due to problems in mitosis. Mitosis occurs in somatic cells and does not contribute to the genetic makeup of gametes that can lead to Down syndrome.

Which of the Following Is True of Down Syndrome