1. **Stating the problem:** We have two parents with alleles at a genetic locus. Parent 1 has alleles A and a, Parent 2 has alleles a and a. We want to find probabilities for offspring genotypes. 2. **Understanding allele inheritance:** Each offspring receives one allele from each parent. Parent 1 can pass either A or a with equal probability $\frac{1}{2}$ each. Parent 2 can only pass allele a (probability 1). 3. **Calculating probabilities:** **a. Probability offspring receives A or a:** Since offspring must receive one allele from each parent, possible alleles are A or a from Parent 1 and a from Parent 2. Thus, offspring alleles are either A and a or a and a. Probability of receiving A (from Parent 1) is $\frac{1}{2}$. Probability of receiving a (from Parent 1) is $\frac{1}{2}$. Parent 2 always passes a. So, probability offspring receives A or a allele is 1 (certain) because offspring always gets either A or a from Parent 1 and a from Parent 2. **b. Probability offspring receives two a alleles:** This happens if Parent 1 passes a (probability $\frac{1}{2}$) and Parent 2 passes a (probability 1). So, probability = $\frac{1}{2} \times 1 = \frac{1}{2}$. **c. Probability offspring receives two A alleles:** Parent 2 has only a alleles, so offspring cannot receive two A alleles. Probability = 0. **Final answers:** - a) Probability offspring receives A or a allele = 1 - b) Probability offspring receives two a alleles = $\frac{1}{2}$ - c) Probability offspring receives two A alleles = 0