$A$ person who is trisomic for the $21^{st}$ pair of chromosomes has:

The cause of Turner's syndrome in humans is:

Match List-$I$ with List-$II$ and select the correct answer using the codes given below:

List-$I$ (Syndrome)	List-$II$ (Chromosomal abnormality)
$(1)$ Patau's syndrome	$(A)$ $44 + XXY = 47$
$(2)$ Klinefelter's syndrome	$(B)$ $44 + X = 45$
$(3)$ Down's syndrome	$(C)$ $46 + 1 = 47$,Chromosome $13^{th}$
$(4)$ Turner's syndrome	$(D)$ $46 + 1 = 47$,Chromosome $21^{st}$

The genotype of a boy having sexual characters of a girl is

Identify the disease on the basis of the following characters:
$(1)$ Short stature with a small round head.
$(2)$ Furrowed tongue and partially open mouth.
$(3)$ Palm is broad with a characteristic palm crease.

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