Add labels to the figure that follows, which illustrates the interacting factors in a declining population that contribute to the extinction vortex.

Which of the following is true of the nitrogen cycle?

The phosphorus cycle lacks a(n) __________ component.

Which of the following organisms is incorrectly paired with its trophic level?a. cyanobacterium—primary producerb. grasshopper—primary consumerc. zooplankton—primary producerd. fungus—detritivore

What is the main global reservoir of nitrogen?

Which of these ecosystems has the lowest net primary production per square meter?a. a salt marshb. an open oceanc. a coral reefd. a tropical rain forest

Fill in the blanks in the table below summarizing terrestrial ­nutrient cycles.

True or False: Most of the net primary productivity that is consumed is used for growth by primary consumers. Explain.

Which of the following is the longest-lived reservoir for carbon?a. atmospheric CO2b. marine plankton (primary producers and consumers)c. fossil fuelsd. wood