What explanation accounts for the absence of Creeper homozygotes in a flock of 98 chicks?

The answer is supported by the idea that the Creeper allele is lethal when expressed in a homozygous state. This means that chicks inheriting two copies of the Creeper allele do not survive, which would account for why none were observed in the flock of 98 chicks. In many genetic scenarios, lethal alleles can be present in a population, but they often lead to death either before birth or shortly after hatching when homozygous.

In this specific case, since every chick with the Creeper phenotype must be heterozygous (having one Creeper allele and one wild-type allele), it results in a situation where only those heterozygous individuals are alive and visible in the flock. This phenomenon is a crucial aspect of genetic inheritance, demonstrating how certain alleles can affect survival and thus the observed genotypic ratios in a population.

Understanding the implications of lethal alleles helps clarify the otherwise puzzling absence of homozygotes and provides insights into the survival implications of genetic traits in a given population.