The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant's diet lacks the amino acid phenylalanine. What maintains the presence of this harmful allele in a population's gene pool? A) heterozygote advantage B) stabilizing selection C) diploidy D) balancing selection

The recessive allele that causes phenylketonuria (PKU) is caused by a genetic factor thereby there is transference of phenylketonuria (PKU) from one generation to another. It is transferred through an Autosomal recessive pattern. This implies that for an offsping to have phenylketonuria (PKU), its progenitor(the male and the female counterpart) must be a carrier of PKU.

Diploidy helps to maintains the presence of the harmful allele(The recessive allele that causes phenylketonuria (PKU)) in a population's gene pool. This is because, the term diploidy refers to a state of having two sets of the chromosomes as such there will be two copies of genes, especially in somatic cells; so the usefulness of Diploidy is to stabilize the chromosome if one of the chromosome(i.e one copy of the gene) is a carrier of PKU.