Question

in goldfish, the twin - tailed trait has two alleles. goldfish that have a heterozygous genotype produce the single - tailed phenotype. this means that goldfish with the twin - tailed phenotype must be _________. mutated homozygous dominant codominant homozygous recessive

Explanation:

In genetics, when a heterozygous genotype produces a different phenotype (single - tailed here), the twin - tailed phenotype must be due to a homozygous recessive genotype. Recessive traits are only expressed when an organism has two copies of the recessive allele.

Answer:

homozygous recessive