A- dominant allele
a- recessive allele
organism that is homozygous dominant, needs to have both alleles being dominant: AA
organism that is heterozygote, needs to have one allele being dominant and the other being recessive: Aa
By making a punnet square (see below), we obtain the genoypes of the offspring:
half of them will be heterozygote (Aa) and the other half (AA) will be homozygous dominant.