Read the following selection and use the passage to answer the following questions Usually, large secondary or tertiary consumers near the top of the food web, such as wolves, sea stars, sharks, and sea otters, are considered keystone
species. Theses predators, control populations of herbivores, which, in the absence of predators, other types, could multiply and greatly change the plant
community. However, other types if organisms also can exert strong community-wide effects. "Ecosystem engineers' physically modify the environment
shared by community members. Beavers build dams and turn streams into ponds that flood acres of dry land and turn them to swamp. Small organisms
and those toward the bottoms of food web may have even greater impact. Remove the fungi that decompose dead matter or the insects that control plant
growth, and a community may change very rapidly indeed.
Question:
Which of the following would make the best BEST title for this selection?
"Keystone Species in Yellowstone Park"
"Defining Trophic Levels
"Surprising Keystone Species
"Do Keystone Species Exist?