Answer the following question given this paragraph: 

The expression of an organism's genotype is called its phenotype . The phenotype refers to the organism's traits, such as purple or white flowers. Different genotypes may produce the same phenotype. This will be the case if one allele is dominant to the other. Both BB and Bb genotypes in Table 6.1 have purple flowers. That's because the B allele is dominant to the b allele, which is recessive. The terms dominant and recessive are the terms Mendel used to describe his "factors. " Today we use them to describe alleles. In a Bb heterozygote, only the dominant B allele is expressed. The recessive b allele is expressed only in the bb genotype.


Q: In a heterozygote with one dominant and one recessive allele, which is expressed?


A:
dominant allele