Answer:
4/4 plants will be tall
Explanation:
For the gene that determines pea plant height, the allele for tallness is dominant to the short allele. We'll say that a true-breeding tall plant is AA and a true-breeding short plant is aa. So for every offspring, the first parent gives a capital A allele and the second parent gives a lowercase a allele, which means that every plant in the F1 generation will have the genotype Aa. However, because that A/tall allele is dominant over the a/short allele, all of the plants will phenotypically appear tall.
