The most common type of mutation that cause cystic fibrosis is a

The most common type of mutation that cause
  cystic fibrosis is a
 
  a. deletion.
  b. insertion.
  c. base-pair substitution.
  d. gene duplication.
  e. transformation

Question 2

In a person who does NOT have cystic
  fibrosis, what is the related normal condition?
 
  a. mucus slides easily over epithelial surfaces
  and can more easily be expelled
  b. osmotic balance in tissues is maintained by
  pumping sodium out of cells and chloride
  into cells
  c. pH balances are maintained by pH buffers,
  mainly the bicarbonate ion
  d. muscle fibers contract in coordination
  allowing smooth whole muscle contractions
  e. plasma membranes function properly to
  allow nonpolar molecules to diffuse into
  and out of the cells