The reason that the various Hawaiian honeycreepers are vulnerable to extinction is

The reason that the various Hawaiian
  honeycreepers are vulnerable to extinction is
  a. the reduction of their habitats.
  b. the warming of their habitats, supporting
  mosquitoes that carry the pathogens for
  avian malaria.
  c. the encroachment of humans into their
  habitats.
  d. the importation of new predators and
  competitors into their habitats.
  e. all of these answers

Question 2

Which of the following has not played a part in
  the extinction of honeycreepers in Hawaii?
  a. Loss of habitat.
  b. Human activities.
  c. Imported species.
  d. Depletion of the ozone layer.
  e. Disease.