A dominant trait is NOT always the more common trait because:
A. sometimes the dominant allele is rare ~ so it rarely shows up.
Dominance refers to the relationship between alleles, where the dominant allele masks the effect of the recessive allele in a heterozygote. However, the frequency of the dominant phenotype in a population can be low if the dominant allele is relatively rare, even if it is dominant. In contrast, a recessive trait can be more common if the recessive allele is more prevalent in the gene pool.