Down syndrome is a disorder of varying severity caused by
A) prenatal viral infections.
B) parental neglect during infancy.
C) an extra copy of chromosome 21.
D) a lack of sufficient oxygen at the time of birth.

Question

Quizplus · Accepted Answer

Down syndrome is caused by the presence of an extra copy of chromosome 21, which leads to developmental and intellectual disabilities. Prenatal viral infections, parental neglect during infancy, and a lack of sufficient oxygen at birth are not direct causes of Down syndrome.

Down Syndrome Is a Disorder of Varying Severity Caused by