The following text is from an environmental science article.
Mangrove forests serve as critical coastal barriers. Their dense root systems absorb wave energy during storms, protecting inland areas from flooding and erosion. Additionally, these roots trap sediment, gradually building new land. The forests also provide nursery habitat for many commercially important fish species.
Which choice best describes the function of the phrase "Their dense root systems absorb wave energy during storms"?
It introduces a new topic unrelated to the opening claim.
It provides specific evidence supporting the claim that mangroves are coastal barriers.
It contradicts the assertion made in the first sentence.
It questions whether mangroves actually protect coastlines.
Correct Answer: B
Choice B is the best answer. The phrase explains HOW mangroves function as "critical coastal barriers" by absorbing wave energy—directly supporting the opening claim.
- Evidence: The first sentence claims mangroves are "critical coastal barriers." The target phrase says roots "absorb wave energy during storms."
- Reasoning: Absorbing wave energy is the mechanism that makes them effective barriers.
- Conclusion: The phrase provides specific evidence to support the initial claim.
💡 Strategy: Relate the specific detail (absorbing waves) to the general statement (coastal barriers).
Choice A is incorrect because it directly relates to coastal protection. Choice C is incorrect because it supports, not contradicts. Choice D is incorrect because it affirms protection, not questions it.