1. What causes cystic fibrosis? 2. Typically, a lethal genetic disorder is very rare. Cystic fibrosis, on the other hand, is the most common potentially lethal genetic disorder among Caucasians. Describe one hypothesis explaining why this is the case. 3. Fill in a Punnett square to visualize the offspring of a cystic fibrosis carrier and a person who doesn't have cystic fibrosis and isn't a carrier. Use F to denote the normal allele and f to denote the mutated CFR allele. 4. What percentage of their children are likely to have cystic fibrosis? 5. What percentage of their children are likely to be carriers of cystic fibrosis?