The following text is about marine biology.
Whales play a crucial but often overlooked role in ocean ecosystems. When they defecate near the surface, they release nutrients that fertilize phytoplankton—tiny organisms that produce about half of Earth's oxygen. When whales die and sink to the ocean floor, their bodies create entire ecosystems, supporting life from sharks to tube worms for decades. Scientists call this the "whale pump" effect, recognizing whales as ecosystem engineers.
According to the text, how do whales contribute to ocean ecosystems?
By eating phytoplankton and controlling their population
By distributing nutrients and supporting life both at the surface and seafloor
By hunting sharks and other predators
By creating coral reefs on their bodies
Correct Answer: B
Choice B is the correct answer. The text describes nutrient distribution at the surface (fertilizing phytoplankton) and ecosystem creation at the seafloor (whale falls).
- Evidence: "Whale pump" nutrients; whale falls support ecosystems.
- Reasoning: Contributions at surface and floor are described.
- Conclusion: Whales support life throughout the ocean column.
Choice A is incorrect because whales fertilize, not eat, phytoplankton. Choice C is incorrect because hunting isn't mentioned. Choice D is incorrect because coral reefs aren't discussed.