An observable trait, such as flower color, is inherited in units of
DNA called genes.
Alternative versions of a gene are called alleles.
An organism's total collection of genes is its genome.
Law of independent assortment.
The P plants of this dihybrid cross are true-breeding: one with
yellow-round seeds and the other with green-wrinkled seeds.
The F dihybrids are heterozygous for both characters.
Self-pollination of the F yields a phenotypic ratio of 9:3:3:1 in
the F, NOT the 3:1 typical of a monohybrid cross.
This id due to the independent assortment of the 2 traits during
meiosis, assuming they are on different chromosomes.
One way to ensure you have all combinations of gametes for a dihybrid
cross is the FOIL method.