Question

Which individual is most likely to allow a recessive lethal gene to be kept in a population over several generations?

heterozygous


homozygous dominant


homozygous recessive

Answer 1

Heterozygous.

A recessive lethal allele is only expressed (and lethal) in homozygous recessive individuals. Heterozygotes carry one copy without showing the lethal phenotype, so they survive and can pass the allele to offspring, maintaining it in the population. Homozygous recessive individuals would die (or fail to reproduce) and homozygous dominants don't carry the allele.