Marine archaeologists recovering wooden artifacts from shipwreck sites face a major challenge: when waterlogged wood dries, the cell walls collapse, causing severe warping and cracking. Historically, researchers attempted to prevent this degradation by slow-drying the wood in controlled humidity chambers, but this method often proved ineffective for highly degraded specimens. To address this issue, conservators introduced polyethylene glycol (PEG), a liquid polymer that replaces the water in the wood cells and solidifies to reinforce the structure. While PEG treatment is time-consuming and expensive, it has become the standard method for stabilizing marine timber, successfully preserving historical vessels like the Swedish ship *Vasa*.
Which choice best describes the overall structure of the text?
- AIt defines a chemical process used in maritime preservation, lists several historical ships preserved by this process, and evaluates the financial costs associated with archaeological excavations.
- BIt contrasts two different chemical preservation techniques, details the chemical composition of each, and argues that one has entirely replaced the other in modern archaeological practices.
- It outlines a threat to preserving certain historical materials, describes an early but flawed strategy for mitigating that threat, details a newer chemical intervention, and concludes by acknowledging a limitation alongside a notable success of this intervention.Cevap
- DIt asserts that traditional preservation methods are superior to chemical treatments, provides examples of failures in modern preservation, and calls for new research into physical drying methods.