Which of the following is an example of a pioneer species?
a. fungus
b. trees
c. shrubs
d. grass

secondary succession can happen after primary succession or independently of primary succession.
a. true
b. false

which of the following about secondary succession is not true?
a. it occurs in ecosystems without soil.
b. it occurs in ecosystems that are already established.
c. it reduces the number of species in an ecosystem.
d. it is