What conclusion can be drawn from research on abundance cycles of Canadian lynx and snowshoe hare? ...

What conclusion can be drawn from research on
  abundance cycles of Canadian lynx and snowshoe
  hare?
  a. A simple predatorprey model explains the
  results.
  b. A simple plantherbivore model explains the
  results.
  c. Raptor activity has no effect on the outcome.
  d. Complex variables are involved.
  e. Manipulation of experimental plots stopped
  cyclic changes in population densities.

Question 2

Predators can switch to alternative prey when a prey
  species is low in abundance as is shown in
  a. model I.
  b. model II.
  c. model III.
  d. models I and III.
  e. all of these models.