A Couple Has a Child with Down Syndrome

question 26

Multiple Choice

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)One member of the couple carried a translocation.
• C)Nondisjunction occurred in one member of the couple during somatic cell production.
• D)Nondisjunction occurred in one member of the couple during gamete production.

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Definitions:

Tree Rings

The concentric rings on the cross-section of a tree trunk, representing a record of a tree's age and the conditions under which it grew.

Paleozoic

An era in the geologic time scale, approximately 541 to 252 million years ago, marked by the early development of life, including the Cambrian explosion.

Geologic Timescale

A system of chronological measurement that relates stratigraphy to time, used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships between events that have occurred during Earth's history.

Precambrian Era

The Precambrian Era encompasses all of geological time prior to the Cambrian Period, covering approximately 88% of Earth's history and marked by the formation of the Earth and the appearance of early life.