If an allele is recessive and lethal in homozygotes before they reproduce, a. the allele will be removed from the population by natural selection in approximately 1,000 years. b. the allele will likely remain in the population at a low frequency because it cannot be selected against in heterozygotes. c. the fitness of the homozygous recessive genotype is 0. d. both b and c are correct.

Verified step by step guidance

1. Understand the concept of recessive lethal alleles, which are alleles that cause the death of the organism when present in a homozygous recessive state.
2. Recognize that in heterozygous individuals, the lethal allele is masked by the dominant allele, allowing these individuals to survive and potentially pass the lethal allele to their offspring.
3. Consider the implications of natural selection on such alleles. Since homozygous recessive individuals do not survive to reproduce, the allele can only be passed on by heterozygous carriers.
4. Analyze the statement that the fitness of the homozygous recessive genotype is 0, which means these individuals do not contribute to the gene pool because they do not survive to reproduce.
5. Evaluate the statement regarding the allele remaining in the population at a low frequency due to its presence in heterozygous individuals, who are not affected by the lethal effects of the allele and can still reproduce.