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Difficulty: HardParagraph Summarization

Galvanic corrosion presents a relentless threat to metal ships operating in saltwater environments, where dissimilar metals submerged in an electrolyte generate an electrical current that accelerates metal degradation. To counteract this deterioration, shipbuilders attach sacrificial anodes—typically blocks of highly reactive zinc or aluminum—directly to the vessel's steel hull. Because these anodes possess a lower electrochemical potential, they corrode preferentially, releasing electrons that safeguard the underlying steel structure. However, once these sacrificial blocks deplete completely, the galvanic reaction immediately targets the hull itself, making scheduled inspections and timely replacement indispensable for preserving structural integrity.

Which of the following statements best summarizes the passage?

  1. A
    Preventative maintenance is essential for extending the operational lifespan and structural safety of all maritime vessels.
  2. B
    Shipbuilders attach zinc and aluminum blocks to ship hulls because their low electrochemical potential allows them to release protective electrons.
  3. Sacrificial anodes protect steel hulls by corroding in place of the ship's metal, but they require periodic inspection and replacement to remain effective.Answer
  4. D
    Galvanic corrosion immediately destroys steel hulls because electrical currents in saltwater permanently accelerate metal degradation.

Answer

Sacrificial anodes protect steel hulls by corroding in place of the ship's metal, but they require periodic inspection and replacement to remain effective.
The correct option encapsulates the complete paragraph by synthesizing the problem of hull corrosion, the protective function of sacrificial anodes, and the critical requirement for regular inspection and replacement upon depletion.

Step-by-Step Solution

1
Identify the central problem introduced in the passage.
Saltwater causes galvanic corrosion between dissimilar metals, threatening steel ship hulls.
Understanding the baseline problem provides the context for the passage's primary focus.
2
Determine the solution and mechanism described by the author.
Sacrificial anodes made of zinc or aluminum corrode preferentially to protect the steel hull.
This represents the primary subject matter of the text.
3
Identify the critical constraint or concluding point.
When anodes deplete, corrosion attacks the hull again, necessitating regular inspection and replacement.
A comprehensive summary must incorporate both the function of the solution and its operational limitation.
4
Synthesize the points and eliminate choices that are too narrow, overly broad, or factually distorted.
The option stating that sacrificial anodes protect steel hulls by corroding in place of the vessel's metal while requiring periodic inspection and replacement is the only complete summary.
An effective summary integrates all core components without omitting essential conditions or generalizing beyond the text.

Key Concept

Paragraph Summarization through synthesis of problem, technical solution, and operational constraint
Estimated Time:1m 15s
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Paragraph Summarization

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