Answer:
Explanation:
Billy's phenotype is his physical appearance. The phenotype is the physical expression of what the gene is made up of.
Billy is polydactyly i.e he has 6 fingers this is his physical expression also known as phenotype and his genotype will be heterozygous dominant(Tt) for the gene to have express itself in the phenotype of billy. He is heterozygous of the gene because his father is recessive of the gene polydactyly
