Based on this information, what is Astro's phenotype for the horns trait?

 - having horns
 - not having horns
You need to determine Astro's phenotype for the horns trait. First, consider the alleles in Astro's genotype for the horns gene. Then, decide whether these alleles are dominant or recessive.
The allele for having horns (h) is recessive to the allele for not having horns (H). This means H is a dominant allele, and h is a recessive allele.
Astro's genotype of Hh has one dominant allele and one recessive allele. An organism with at least one dominant allele for a gene will have the dominant allele's version of the trait. So, Astro's phenotype for the horns trait must be not having horns.