Punnett square are used to predict the possibility of different outcomes. when looking at one trait at a time it is called a monohybrid cross. you completed these last year. complete the review problem below. review: cross a heterozygous male for tallness with a homozygous recessive female for tallness. then give the genotype and phenotype ratios. dihybrid crosses involve tracking two traits simultaneously. for example, we can predict the outcome for offspring as the traits for both height and color are concerned.