Which of the following disorders does not result in a sterile individual?

The chromosomal condition $2n-1$ is an example of what?

Which one of the following genetic disorders is $CORRECTLY$ matched with its karyotype?

Which event in the chromosomal structure leads to the formation of a syndrome?

$A$ male individual with $47$ chromosomes due to the addition of an $X$ chromosome suffers from a condition called:

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?