As Successional Changes Occur in an Ecosystem,new Species Take Advantage

Multiple Choice

As successional changes occur in an ecosystem,new species take advantage of new conditions.Where do these new species come from?

A) They evolve from other species in the immediate region.
B) They come from surrounding ecosystems in other stages of succession.
C) They are planted by forest rangers managing these forest ecosystems.
D) The seeds of the new species are carried in by large streams and rivers.