Nancy and Cliff had four children who did not have cystic ...

[appyboo]

Nancy and Cliff had four children who did not have cystic fibrosis, but their fifth child was born with the disease. Cystic fibrosis is carried on a recessive gene. Given what you've learned in this chapter, how could this happen?
 
  a. It wasn't until the fifth child that both parents passed on the allele for this illness.
 b. Recessive genes normally skip a generation, but after the parents had five children, the gene was expressed.
  c. Their fifth child must have been a boy, which makes it more probable that he would have the illness.
 d. Their fifth child must have been a girl, which makes it more probable that she would have the illness.

Question 2

When either a mother's or father's version of a gene is expressed, but not both, we refer to the gene as
 
  a. imprinted.
 b. dominant.
 c. recessive.
 d. an SNP.

[Bsand8]

Answer to Question 1

a

Answer to Question 2

a