How can a dominant gene and a recessive gene, affect the offsprings genes

A dominant allele produces a dominant phenotype in individuals who have one copy of the allele, which can come from just one parent. For a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent.

Explanation:

A dominant allele becomes a trait even if just one copy of it is present. A recessive allele does not become a trait unless both copies of the gene, one from mom and one from dad, are present. If one dominant allele and one recessive allele are present, the dominant allele trait will be expressed.

Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait.