Answer the following question given this paragraph: 

What happens when there are two alleles in a heterozygote and neither allele is completely dominant nor completely recessive? Can both traits appear in the phenotype? Essentially, yes they can. Can there be two dominant alleles for the same gene? Codominance occurs when both traits appear in a heterozygous offspring. For example, roan shorthorn cattle have codominant genes for hair color. The coat has both red and white hairs; not pink hairs, but red AND white hairs. The letter R indicates red hair color, and R’ white hair color. In cases of codominance, the genotype of the organism can be determined from its phenotype. The heifer in Figure below shows both coat colors and therefore is RR’ heterozygous for coat color. The flower in Figure below also has two codominant alleles; it has red and white petals, not pink petals. Both colors appear in the phenotype.


Q: What is said to occur when both traits appear in a heterozygous offspring?

 Choices:

- identical twins

- pollenation

- xenophobia

- codominance

A:
codominance
