Punnett squares use mathematical probability to help predict the genotype and phenotype combinations in genetic crosses. Select the steps below that describe how to construct Punnett squares. A. All possible combinations of alleles in the gametes produced by one parent are written along the top edge of the square. B. All possible combinations of alleles of the other parent are written along the left edge of the square. C. All possible genotype are written inside the boxes within the square, as they might appear in the offspring. D. All possible combinations of phenotypes are written at both edges of the square.