In this monohybrid genetics activity, students in Lee Causey and Stephanie Summerlin’s classes at C.A. Gray examined plastic eggs that had been labeled with genotypes for the egg and sperm represented by each half of the egg. Students created Punnett squares — diagrams that show the different crosses available from specific genotype combinations. The students used the squares to determine what offspring would be possible from each cross, then determined the ratio for possible phenotypes and genotypes represented by each cross. Within each egg were jellybeans representing the correct phenotypes for each cross.