Dominant traits are traits that are visible in the phenotype of an organism.
If barking is dominant in some allele of the dog and it has both male and female then a cross between the male and female with the dominant allele for barking will give a strain of pure breeder barkers.
A recessive allele cannot breed a pure barker because it does not have the allele for barking.
Hence a cross between two individual that dominos of the allele will breed true type.
DNA stands for deoxyribonucleic acid. RNA stands for ribonucleic acid. Both RNA and DNA contain Adenine, Cytosine, and Guanine. However, DNA's nitrogenous base is Thymine while RNA's nitrogenous base is Uracil.