Match the following:

Column-$I$	Column-$II$
$(1)$ Inheritance of two genes	$(a)$ $ABO$ blood group
$(2)$ Incomplete dominance	$(b)$ $1:2:1$
$(3)$ Codominance	$(c)$ $9:3:3:1$
$(4)$ Inheritance of one gene	$(d)$ $3:1$

In a dihybrid cross,when one pair of alleles shows incomplete dominance,the resulting genotypic ratio will be ....

Which one of the following symbols and its representation, used in human pedigree analysis, is correct?

$ABO$ blood type in man is an example of
$A$. Pleiotropy
$B$. Incomplete dominance
$C$. Co-dominance
$D$. Multiple allelism
Select the code for the correct answer from the options given below.

In a plant,three dominant genes $A$,$B$,and $C$ must be expressed together to produce purple flowers. If any one or all three genes are in the recessive state,the flowers become colorless.
Raw material $\xrightarrow{A} X \xrightarrow{B} Y \xrightarrow{C} Z$ (Pigment)
$A$ purple-flowered plant with genotype $AABBCC$ is crossed with a colorless plant with genotype $aabbcc$. This results in $F_1$ hybrid purple offspring. What will be the proportion of purple-flowered plants in the $F_2$ generation produced by selfing the $F_1$ generation?

$A$ person may have one gene for normal haemoglobin and one gene for sickle cell haemoglobin. This heterozygous condition is called: