In corn populations, a lethal albino allele persists because

• A. the seeds were old and stored improperly, resulting in the lethal trait
• B. the parent plants carried the recessive gene for the albino trait
• C. the soil nutrients will not allow the plant to produce chlorophyll.
• D. the farmer used herbicides, which destroyed the chlorophyll in the seedlings.

Answer: (B)

A recessive allele can persist in a population because individuals carrying one copy (heterozygotes) appear normal and can reproduce, so they continue to pass the allele to their offspring. With an albino trait that is lethal only when two copies are present, the albino phenotype shows up only in homozygous recessives, who often die or are removed from the population. However, the allele remains in the gene pool because the carriers keep transmitting it to the next generation. That’s why parent plants carrying the recessive albino gene explain why the allele persists. The other options describe environmental or non-genetic factors, which don’t explain how a genetic allele remains in a population.