Which of the following are heterotrophs?

Which of the following are heterotrophs?
  a. primary carnivores
  b. herbivores
  c. detritivores
  d. decomposers
  e. all of these

Question 2

Which of the following is NOT true of ecosystems?
  a. Although they may include many different
  species, many features of ecosystem structure
  and function are alike.
  b. Autotrophs secure energy and nutrients that are
  then used by heterotrophs.
  c. Energy cycles and minerals flow through
  ecosystems.
  d. Many different food chains are represented in
  most ecosystems.
  e. Ecosystems are characterized by relatively few
  trophic levels