Question

what percentage of the offspring will be purebred dominant?

Explanation:

Step1: Identify purebred dominant genotype

Purebred dominant is $YY$.

Step2: Count total offspring genotypes

From the Punnett square, total genotypes: $YY, Yy, Yy, yy$ → 4 total.

Step3: Count purebred dominant cases

Only 1 case of $YY$.

Step4: Calculate percentage

$\text{Percentage} = \frac{\text{Number of } YY}{\text{Total offspring}} \times 100\% = \frac{1}{4} \times 100\%$

Answer:

25%