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