Successful geographic dispersal occurs by

Successful geographic dispersal occurs by
  a. expansion of home range.
  b. jump dispersal across great distances.
  c. continental drift.
  d. all of these.
  e. none of these.

Question 2

The above graph demonstrates
  a. how periwinkle population density can act to
  stabilize a community.
  b. how diversity of algal groups peaks when the
  periwinkle population goes down.
  c. as periwinkle populations increase, algal
  diversity remains constant.
  d. the rate of the tide is the strongest influence on
  the population of algae.
  e. all of these.