Dennis is mentally retarded. He has a flat nose,a protruding tongue,and upwardly slanted eyes. Which of the following statements is most likely to be true
A) Dennis has Down syndrome, caused by an extra 21ˢᵗ chromosome.
B) Dennis has Down syndrome, caused by missing 21ˢᵗ chromosome.
C) Dennis has Down syndrome, caused by maternal alcohol consumption.
D) Dennis has Down syndrome, caused by a lack of oxygen during birth.

Question

Dennis is mentally retarded.  He has a flat nose,a protruding tongue,and upwardly slanted eyes.  Which of the following statements is most likely to be true
A)  Dennis has Down syndrome, caused by an extra 21ˢᵗ chromosome.
B)  Dennis has Down syndrome, caused by missing 21ˢᵗ chromosome.
C)  Dennis has Down syndrome, caused by maternal alcohol consumption.
D)  Dennis has Down syndrome, caused by a lack of oxygen during birth.

Quizplus · Accepted Answer

Dennis displays physical characteristics consistent with Down syndrome, which is caused by an extra copy of the 21ˢᵗ chromosome. The other options are not consistent with the symptoms he displays.

Dennis Is Mentally Retarded