Mendel's First Law
All hybrid offspring resulting from the cross between two homozygous individuals are equal to each other.
When two pure races are crossed (a dominant homozygous with a recessive one) for a certain trait, all the descendants of the first generation (F1) will be equal to each other, phenotypically and genotypically, and phenotypically equal to one of the parents (genotype dominant), regardless of the direction of the cross. The corresponding character is called dominant (A = yellow), and recessive (a = green) which is masked.
A = Yellow seed; a = green seed. A > a
P AA * aa or aa * AA
F 1 All Aa
F 1 100% All yellow seeds.