Question

if aa, aa, and aa are the possible genotypes of the offspring in a cross, then what are the parent genotypes?
a aa and aa
b aa and aa
c aa and aa
d aa and aa

Explanation:

Step 1: Analyze each option

• Option a: When crossing AA and Aa, the possible genotypes of offspring are AA and Aa. Using a Punnett - square, the parent with genotype AA can only contribute A, and the parent with genotype Aa can contribute A or a. So the possible combinations for offspring are AA and Aa.
• Option b: When crossing Aa and aa, the possible genotypes of offspring are Aa and aa.
• Option c: When crossing Aa and Aa, the possible genotypes of offspring are AA, Aa, and aa.
• Option d: When crossing AA and AA, the only possible genotype of offspring is AA.

Answer:

a. AA and Aa