Which of the following is $NOT$ an example of incomplete sex-linkage (pseudo-autosomal inheritance)?

Give differences: Incomplete dominance and Co-dominance.

Match List-$I$ with List-$II$ :

List-$I$	List-$II$
$A$. Incomplete Dominance	$I$. Human skin colour
$B$. Co-dominance	$II$. Inheritance of flower colour in Antirrhinum sp.
$C$. Pleiotropy	$III$. Phenylketonuria disease in humans
$D$. Polygenic inheritance	$IV$. $ABO$ blood group

Choose the correct answer from the options given below :

The number of chromosomes present in a gorilla is:

State how many of the given statements are correct.
$(1)$ In a dihybrid cross experiment,Mendel obtained a test cross ratio of $1:1:1:1$.
$(2)$ Coupling and repulsion were first explained by Bateson and Punnett.
$(3)$ Klinefelter syndrome is a sex-chromosomal disorder occurring in females.
$(4)$ Mendel selected $7$ pairs of contrasting traits in pea plants to explain his experiments.
$(5)$ The chromosomal theory of inheritance was first proposed by Sutton and Boveri.

Among the four couples given,who could be the biological parents of a child with $O^+$ blood group?