In a Punnett square, what are the expected combinations for offspring alleles?

In a Punnett square, the expected combinations for offspring alleles are derived from the genotypes of the parents. In choice A, GG/Gg and Gg/gg represent a typical scenario where the dominant and recessive alleles are crossed. Here, assuming one parent has the genotype GG and the other has Gg, the possible combinations for the offspring would be GG or Gg.

The correct answer illustrates the typical way Punnett squares work in predicting the genotype frequencies for offspring from the parental generation. The offspring combinations reflect the potential genetic makeup that can arise based on the allele contributions of each parent, adhering to the principles of Mendelian genetics. This allows predictions about the inheritance patterns of traits based on the alleles contributed by the parents.

The other options do not accurately represent the expected combinations that one would see when filling out a Punnett square based on conventional crosses. Each of the combinations in those choices contains alleles or combinations that do not align with standard genetic principles as clearly as those represented in choice A.