Answer:
The expected ratio of the F_2 generation from F_1 generation will be
9 "fabulous": 3 "smashing": 4 "plain"
Explanation:
The expression of the phenotype will follow Mendel's Dihybrid cross.
plain→smashing
(only when allele A is present, which produces Enzyme 1)
smashing→fabulous
(only when allele B is present, which produces Enzyme 2)
Keeping the above statements in mind, in F_2 generation, only the genotypes having both A and B alleles will express phenotype "fabulous",as both Enzyme 1 and Enzyme 2 are required for that. The genotype having at-least one A allele and no B allele will produce the phenotype "smashing", as Enzyme 1,produced by allele A, will convert "plain" into "smashing". Hence, the dihybrid cross will as in the attachment.
