Updated - Now with 9 worksheets! There are 6 worksheets which serve as a great introduction to the ideas of genotypes, phenotypes and basic Punnett squares. Now there are 3 new worksheets which cover the topic of dihybrid crosses including the calculation of phenotype and genotype combinations. Dihybrid crosses are presented using two 2x2 squares that even younger students will be able to master. All of these worksheets were developed by a high school science instructional specialist with a degree in biochemistry and genetics. This is an incredible value!