If the haploid chromosome number in a cell is $12$,then the monosomic number will be:

$A$ man having Klinefelter's syndrome is

$A$: Turner's syndrome generally does not occur in males.
$R$: Foetus with $44 + YO$ complement generally dies.

Which of the following statements are correct about Klinefelter's Syndrome?
$A$. This disorder was first described by Langdon Down $(1866)$.
$B$. Such an individual has overall masculine development. However,the feminine development is also expressed.
$C$. The affected individual is short statured.
$D$. Physical,psychomotor and mental development is retarded.
$E$. Such individuals are sterile.
Choose the correct answer from the options given below:

Mark the odd one with respect to the syndrome which occurs due to the failure of segregation of homologous pairs of chromosomes during the cell division cycle.

An abnormal male child is born to normal parents. This child shows a short neck,stubby hands,slanting eyes,a permanently open mouth with a projecting upper lip,and short stature. This abnormality can be attributed to: