Question

2 multiple choice 20 points in a cross between two heterozygous parents (aa x aa), what is the probability of an offspring being homozygous recessive? 100% 25% 50% 75%

Explanation:

Step1: Use Punnett Square

For parents \( Aa \times Aa \), the possible gametes from each parent are \( A \) and \( a \). The Punnett Square is:

	A	a
a	Aa	aa

Step2: Calculate Probability

There are 4 possible genotypes. The homozygous recessive (\( aa \)) occurs 1 time. So probability is \( \frac{1}{4} = 25\% \).

Answer:

25% (corresponding to the option with "25%")