The following text is about environmental science.
Ocean acidification, often called climate change's "equally evil twin," occurs as oceans absorb atmospheric carbon dioxide. The CO2 dissolves and forms carbonic acid, lowering ocean pH. This process threatens marine organisms that build shells or skeletons from calcium carbonate, including corals, oysters, and certain plankton. As these species struggle, entire food webs may collapse. Scientists warn that current acidification rates exceed any in the past 300 million years, giving ecosystems little time to adapt.
What is the main concern about ocean acidification?
It only affects deep-sea environments
It threatens shell-building organisms with cascading ecosystem effects
It has occurred many times before at similar rates
It benefits coral reef growth
Correct Answer: B
Choice B is the correct answer. The text describes threats to shell-building organisms and warns "entire food webs may collapse."
- Evidence: Corals, oysters, plankton threatened; food web collapse possible.
- Reasoning: Individual species effects cascade through ecosystems.
- Conclusion: Threat to shell-builders with ecosystem-wide impacts.
Choice A is incorrect because surface organisms like corals are affected. Choice C is incorrect because current rates "exceed any in the past 300 million years." Choice D is incorrect because corals are among those threatened.