How does a gastrovascular cavity differ from a complete digestive tract?

How does a gastrovascular cavity differ from a
  complete digestive tract?
 
  a. a gastrovascular cavity has an opening that
  serves as a mouth and an anus
  b. the complete digestive process is slower in
  a gastrovascular cavity
  c. there is less specialization of parts in a
  gastrovascular cavity
  d. the four functions of digestion are not
  simulataneous in a gastrovascular cavity as
  they are in a complete digestive tract
  e. all of these are differences between a
  gastrovascular cavity and a complete
  digestive tract

Question 2

In which of these animals is a gastrovascular
  cavity found?
 
  a. flatworms
  b. sea anemones
  c. earthworms
  d. monkeys
  e. more than one of animals has a
  gastrovascular cavity