Which statement about cystic fibrosis is true?
A.) Cystic fibrosis is caused by a deletion of one codon in the DNA molecule.
B.) Cystic fibrosis affects a person's ability to make normal red blood cells.
C.) Carriers have an advantage over people who do not have the cystic fibrosis mutation.
D.) Cystic fibrosis is caused by a mutation in which a dominant allele replaces a recessive allele.