Question

Cystic fibrosis, a disease that causes an accumulation of mucus in the lungs, results when a person is homozygous recessive for the autosomal trait (ff). If two parents who do not have cystic fibrosis give birth to a baby with cystic fibrosis, what are the parents’ genotypes?

1)Ff,Ff
2)ff,ff
3)FF,Ff
4)FF,FF

Answer 1

#1 is the answer since there's a 25% chance that they will have a baby with Cystic fibrosis all the other answers would cause the baby to not have it or for the parents to have it.