Down’s syndrome in humans is due to
three $‘X’$ chromosomes
three copies of chromosome $21$
monosomy
two $‘Y’$ chromosomes.
The condition in which there are more than two complete set of chromosome is called
Find out correct pair.
$A$ : Turner's syndrome generally does not occur in males.
$R$ : Foetus with $44 + YO$ complement generally dies.
In Down's syndrome $(Mongolism)$ each cell has how many chromosomes
Number of sex chromosomes is normal in