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:

Step1: Analyze option a

If parents are AA and Aa, AA can only pass on A - allele and Aa can pass on A or a - allele. The possible genotypes of offspring are AA (from A of AA and A of Aa) and Aa (from A of AA and a of Aa).

Step2: Analyze option b

If parents are Aa and aa, Aa can pass on A or a - allele and aa can only pass on a - allele. The possible genotypes of offspring are Aa and aa, not AA.

Step3: Analyze option c

If parents are Aa and Aa, using Punnett - square analysis, the possible genotypes of offspring are AA, Aa, and aa.

Step4: Analyze option d

If parents are AA and AA, they can only pass on A - allele, and all offspring will be AA, not Aa or aa.

Answer:

a. AA and Aa