A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child's condition?
A) The woman inherited this tendency from her parents.
B) The mother had a chromosomal duplication.
C) One member of the couple underwent nondisjunction in somatic cell production.
D) The mother most likely underwent nondisjunction during gamete production.
D
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a. true b. false
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