The reduction of one pair of chromosomes in humans is due to:

The diagrammatic representation of the chromosomes of an individual is called

Turner's syndrome is characterized by which of the following chromosomal constitutions?

In humans,sometimes during gametogenesis,sex chromosomes do not separate,resulting in a chromosome number of $45$,$47$,or $48$. In this condition,which of the following genotype and phenotype combinations is correct?

Match Column $-I$ with Column $-II$ and select the correct option.

Column $-I$	Column $-II$
$(P)$ Turner syndrome	$(i)$ Sex chromosome $(2n-1)$
$(Q)$ Down syndrome	$(ii)$ Sex chromosome $(2n+1)$
$(R)$ Klinefelter syndrome	$(iii)$ Autosomal $(2n+1)$

Turner's syndrome is caused due to the absence of ........ chromosomes.