Over time, natural selection eliminates individuals with detrimental phenotypes from a population. however, there are several examples in the human population in which harmful genetic polymorphisms are maintained. why? a. individuals with two wild type alleles have advantages over individuals carrying the harmful allele. b. individuals with two harmful alleles have advantages over individuals carrying one copy of the harmful allele. c. homozygous individuals have some other advantage over individuals with two wild type alleles. d. heterozygous individuals have some other advantage over individuals with two wild type alleles.