All the answers are correct .The dominant character can how its effects or phenotype in both homozygous and heterozygous conditions .A recessive allele can only shows its phenotypes or trait when it is present in the homozygous conditions . Most of them are present in the homozygous conditions and thus the alleles can express themselves. In this condition we have seen here that a person with “hh” genotype will have a hitchhiker’s thumb .