Question

Which chromosome is affected?

a) Chromosome 21
b) Chromosome X
c) Chromosome 13
d) Chromosome 18

Answer 1

Down syndrome is caused by the complete or partial trisomy of chromosome 21.

Step-by-step explanation:

Down syndrome is caused by the complete or partial trisomy of chromosome 21. This means that there is an extra copy of chromosome 21 present in the cells. Therefore, the correct answer is a) Chromosome 21.