What genotype pair indicates both alleles are expressed equally in offspring?

The genotype pair that indicates both alleles are expressed equally in offspring is represented by AB. This is an example of codominance, a genetic scenario where both alleles influence the genotype and phenotype of the organism without one being dominant over the other.

In the case of the AB genotype, when an offspring inherits one A allele and one B allele, both traits associated with these alleles will be visibly expressed. For instance, in a situation involving blood types, an individual with genotype AB will express both A and B antigens on their red blood cells, showcasing that both alleles are contributing equally.

The other options represent genotypes that do not convey equal expression from two differing alleles. For example, AA and BB depict homozygous genotypes with only one allele being present, leading to expression solely of the dominant trait. OO similarly denotes a genotype with no diversity in alleles; therefore, it can only result in the expression of a single trait.