Alarge population of laboratory animals has been allowed to breed randomly for a number of generations. after several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. the rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. what is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time?

A constant allele frequency is maintained by populations in absence of natural selection as both the alleles for the trait impart equal survival advantage (adaptive) to the individuals under the prevailing conditions.

Explanation:

A population maintains constant allele frequencies in absence of evolutionary forces such as natural selection. This occurs when the existing allele frequencies of a gene are adaptive to the individuals. Both the alleles for a trait should be equally beneficial in terms of survival and reproductive success of the individuals under the given conditions. Therefore, both the alleles are maintained with existing frequencies.

the endomembrane system i think