Down Syndrome Occurs When There Is an Extra Chromosome #21

Multiple Choice

Down Syndrome occurs when there is an extra chromosome #21.Such individuals therefore have 47 chromosomes.Assume that a mating occurs between a female with Down Syndrome and a normal male.Assuming normal disjunction during meiosis,what percentage of offspring would be expected to have Down Syndrome?

A) 25%
B) 50%
C) 75%
D) 100%
E) 0%