Explain the following terms with examples:
$(a)$ Co-dominance
$(b)$ Incomplete dominance

(N/A) Co-dominance
Co-dominance is the phenomenon in which both alleles of a gene pair are expressed equally in the heterozygous condition. Neither allele is dominant or recessive over the other. $A$ classic example is the $ABO$ blood group system in humans. The blood group is controlled by three alleles: $I^{A}, I^{B},$ and $i$. The alleles $I^{A}$ and $I^{B}$ are equally dominant and are co-dominant,as both are expressed in individuals with the $AB$ blood group,producing both $A$ and $B$ antigens on the surface of red blood cells.
$(b)$ Incomplete dominance
Incomplete dominance is a phenomenon in which one allele is not completely dominant over the other allele of the same gene pair,resulting in a phenotype that is intermediate between the two parental traits. For example,in the snapdragon plant ($Antirrhinum$ species),a cross between red-flowered $(RR)$ and white-flowered $(rr)$ plants results in pink-flowered $(Rr)$ plants in the $F_{1}$ generation. The $F_{1}$ progeny does not resemble either parent but exhibits an intermediate phenotype because the dominant allele $R$ is only partially dominant over the recessive allele $r$.