Which Cross Shows Both Parents Having Two Different Alleles for Each

Question

Which cross shows both parents having two different alleles for each of two different genes?
A) AAbb × aaBB
B) aabb × AABB
C) AaBb × AaBb
D) AaBB × AABb

Accepted Answer

In the cross AaBb × AaBb, both parents have two different alleles for each of two different genes (A/a and B/b). Option A shows both parents being homozygous for their respective genes, option B shows both parents being homozygous and having the same alleles, and option D shows one parent being homozygous for one gene and heterozygous for another, while the other parent is heterozygous for both genes; thus, these three options do not fit the criteria specified in the question.