Question

down syndrome (trisomy 21) can be diagnosed prenatally by examining the individuals.
○ parents genotypes.
○ karyotype.
○ kinetochores.
○ sex chromosomes.
○ haploid/diploid/triploid state.

Explanation:

Down syndrome (Trisomy 21) is caused by an extra copy of chromosome 21. A karyotype is a visual display of an individual's complete set of chromosomes, which can clearly show the presence of three copies of chromosome 21. Parents' genotypes do not directly diagnose the fetal condition; kinetochores are chromosome structures unrelated to this diagnosis; sex chromosomes are not involved in Trisomy 21; and the haploid/diploid/triploid state does not specifically identify the extra chromosome 21.

Answer:

karyotype.