In temperate marine ecosystems, the interactions among sea otters, sea urchins, and giant kelp forests demonstrate the profound impact of a trophic cascade. Kelp forests serve as a vital marine habitat, but they are constantly threatened by herbivorous sea urchins that feed aggressively on kelp holdfasts. Fortunately, sea otters prey on these urchins, maintaining their numbers at a level that prevents them from overgrazing the kelp. When sea otters are hunted to near extinction, the urchin population expands exponentially, rapidly deforesting the seabed and turning a diverse habitat into a barren wasteland. In this relationship, the predator's pressure on a consumer indirectly safeguards the primary producer, preserving the entire ecological community.
Which of the following situations is most analogous to the relationship between the sea otters, sea urchins, and giant kelp forests described in the passage?
- AA commercial landlord offers discounted rent to a popular coffee shop because its daily foot traffic attracts customers who then patronize adjacent retail stores.
- BA city constructs a concrete seawall along the coast to block high tides from flooding low-lying residential neighborhoods during major storms.
- A government watchdog agency caps the transaction fees charged by payment processors, preventing them from depleting the narrow profit margins of independent merchants who sustain a community’s commercial district.Answer
- DA school board hires additional guidance counselors to directly assist students struggling with academic stress, thereby improving overall graduation rates.