The inheritance of $ABO$ blood group is an example of which of the following conditions?
$I -$ Complete dominance,$\quad II -$ Co-dominance
$III -$ Multiple allelism,$\quad IV -$ Incomplete dominance

Read the following statements carefully $:-$
$(a)$ Linkage is physical association of genes on a chromosome.
$(b)$ In $Drosophila$, genes of body colour and eye colour are tightly linked on $X$-chromosome.
$(c)$ In honey bee a fertilised egg develops as a male $(drone)$.
$(d)$ In grasshopper males have only one $X$-chromosome besides the autosomes.
$(e)$ $Drosophila$ can complete their life cycle in about two months.
Choose the correct option having all correct options.

With the help of an example,differentiate between incomplete dominance and co-dominance.

Sickle-cell anemia has not been eliminated from the African population because,........

Match the following (Column-$I$ with Column-$II$):

Column-$I$	Column-$II$
$(P)$ $(2n-1)$	$(i)$ Produces normal female
$(Q)$ $Hb^s Hb^s$	$(ii)$ Produces haploid male
$(R)$ $22AA+XX$	$(iii)$ Causes Turner syndrome
$(S)$ $(X+O)$	$(iv)$ Causes sickle cell anemia
	$(v)$ Causes hemophilia
	$(vi)$ Shows Klinefelter syndrome

Theoretically,the phenotype is expressed only when an enzyme converts a substrate into its product. During which of the following conditions is the phenotype affected?