Answer:
A. AaBb x AaBb
Explanation:
The term heterozygous refers to the presence of two different alleles of same gene in an organism. The one allele can be of wild type (original type) and one can be mutated or newly formed.
In the question, two traits are represented by two letters, A and B and alleles as A and a and B and b, respectively. We are asked about a cross involving two traits and two individuals in such a way that both are heterozygous.
If we look at option A, AaBb x AaBb,
we see that one trait A and the other trait B is in heterozygous form (Aa and Bb) in both individuals.
If we look at option B. AABB x AABB
we see that one trait A and the other trait B is in homozygous form form (AA and BB) in both individuals. Homozygous means when the alleles are same for each trait in an individual.
If we look at option C,Aa x Bb
There are not two traits, one trait of one individual and other trait of other individual is being crossed that is not possible.
If we look at option D. AAaa x BBbb
Again, the individuals are homozygous for two traits.
Therefore, A is best option.
Hope it helps!
