The allele for cystic fibrosis is recessive. what does this mean? a. the allele for cystic fibrosis is only passed along when a person carrying it is homozygous for it. b. cystic fibrosis will kill any person with that allele. c. cystic fibrosis never affects anyone with the allele--it is only carried. d. cystic fibrosis can be carried in a heterozygote and kill a homozygous offspring.