Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/linkage?

Which one of the following is a type of hyperploidy?

An abnormal human male phenotype involving an extra $X$ chromosome $(XXY)$ is a case of

Which of the following disorders exhibits sex chromosomal monosomy?

Down's syndrome is an example of

Three copies of chromosome-$21$ in a child with Down's syndrome have been analysed using molecular biology technology to detect any possible $DNA$ polymorphism with reference to different alleles located on chromosome-$21$. Results showed that out of $3$ copies,$2$ of the chromosomes of the child contain the same alleles as one of the mother's alleles. Based on this,when did the non-disjunction event most likely occur?