In humans, cystic fibrosis is an inherited autosomal recessive disorder. A genetic counsellor is mapping the potential offspring of two parents who are both heterozygous carriers of the mutated gene (Ff, where F represents the dominant healthy allele and f represents the recessive mutated allele).

Complete the Punnett square by identifying the correct genotypes for the empty cells (i), (ii), (iii), and (iv).