The following text discusses ocean acidification.
Ocean acidification is called climate change's "evil twin" because both result from carbon dioxide emissions. As oceans absorb CO2, chemical reactions lower the water's pH level. This increasing acidity threatens marine organisms, particularly those with calcium carbonate shells like oysters and coral. Scientists warn that continued acidification could disrupt entire marine food chains.
Which choice best describes the overall structure of the text?
It introduces a phenomenon, explains its cause, and describes its effects.
It compares ocean acidification to other environmental problems.
It provides solutions for reducing ocean acidity.
It traces the historical discovery of ocean chemistry.
Correct Answer: A
Choice A is the best answer. The text introduces ocean acidification, explains its cause (CO2 absorption), and describes effects (threat to marine life).
- Evidence: The text introduces "Ocean acidification." It explains cause: "oceans absorb CO2." It describes effects: "threatens marine organisms."
- Reasoning: The flow is Phenomenon -> Cause -> Effect.
- Conclusion: This matches "introduces... explains cause... describes effects."
💡 Strategy: Track the logical flow: What -> Why -> So what?
Choice B is incorrect because detailed comparison isn't the focus. Choice C is incorrect because no solutions are provided. Choice D is incorrect because historical discovery isn't traced.