Roan cattle show codominance for the color of their hair. there are alleles for red hair and white hair. what would you expect a heteozygous roan bull to look like if the trait showed incomplete dominance instead?

The answer is pink.

In incomplete dominance, a heterozygous phenotype is intermediate between two homozygous phenotypes. For this phenomenon, the symbols for alleles are capital letters. For example, allele A is responsible for red color of a hair, allele B is responsible for white color of the hair. Red cattle have AA genotype, and white cattle have BB genotype. By crossing cattle with red hair (AA) and white hair (BB), due to incomplete variance, the offspring will be heterozygous cattle (AB) with neither red nor white hair, but pink hair. Pink is an intermediate color between red and white.