Consider statements about genetics: 1. Aneuploidy is caused by the failure of chromatids to separate. 2. Down syndrome is caused by trisomy 21. 3. Turner syndrome has the karyotype 47, XXY. Which are correct? MCQ with Answer and Explanation

Aneuploidy is a chromosomal abnormality resulting from nondisjunction, the failure of homologous chromosomes or sister chromatids to separate properly during cell division. Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21 (trisomy 21). Turner syndrome is a sex chromosome anomaly in females characterized by the karyotype 45, X0, not 47, XXY (which is Klinefelter syndrome). Thus, statements 1 and 2 are correct.