JAMB Biology 2021 Paper

Concept:When both parents are heterozygous, each parent can pass on either the dominant allele $A$ or the recessive allele $a$.Explanation:Let the genotype of each parent be $Aa$.The possible gametes from each parent are $A$ and $a$.Combining these gametes gives the offspring genotypes: $AA$, $Aa$, $aA$, and $aa$.Only $aa$ shows the recessive trait.Out of 4 equally likely outcomes, only 1 is $aa$.So, the probability of a recessive offspring is $\frac{1}{4}$.Answer:Option B: $\frac{1}{4}$