To solve this problem, we need to identify which pair is incorrectly matched. Let's analyze each option:$\newline \bullet$Option 1: XO type sex determination - Grasshopper$\newline$ - In grasshoppers, sex determination follows the XO system, where males have one X chromosome (XO) and females have two (XX).$\newline$ - This is correctly matched.$\newline \bullet$Option 2: ABO blood grouping - Co-dominance$\newline$ - The ABO blood group system is an example of co-dominance, where both A and B alleles are expressed in the phenotype.$\newline$ - This is correctly matched.$\newline \bullet$Option 3: Starch synthesis in pea - Multiple alleles$\newline$ - Starch synthesis in pea plants is controlled by a single pair of alleles, not multiple alleles.$\newline$ - This is incorrectly matched.$\newline \bullet$Option 4: T.H. Morgan - Linkage$\newline$ - T.H. Morgan is known for his work on linkage and gene mapping in Drosophila.$\newline$ - This is correctly matched.$\newline$Therefore, the pair that is wrongly matched is Option 3: Starch synthesis in pea - Multiple alleles.