Question

cross aa × aa
what is the genotypic ratio of the offspring?
(options: 2:2, 3:1, 1:2:1, 1:3)

Explanation:

Step1: Identify offspring genotypes

From the Punnett square, the genotypes are: $AA$, $Aa$, $Aa$, $aa$

Step2: Count each genotype

Count of $AA$: 1; Count of $Aa$: 2; Count of $aa$: 1

Step3: Form the genotypic ratio

Ratio is $AA:Aa:aa = 1:2:1$

Answer:

1:2:1