In the sentence "The F2 generation phenotypes resulting from the monohybrid cross of purebreds display a ratio of _____" the word that correctly completes the sentence is 3:1. In the monohybrid cross of purebreds, F1 generation will consist of heterozygotes with dominant phenotype. When F1 generation cross, the F2 generation phenotypes will be as following: 3 dominant phenotypes (1 dominant homozygote and 2 heterozygotes) and 1 recessive phenotype (1 recessive homozygote).