Question

In the mid-nineteenth century, the global expansion of submarine telegraphy encountered a fundamental technological bottleneck: the rapid degradation of undersea cable insulation when exposed to high hydrostatic pressures and saline environments. Early attempts using vulcanized rubber proved disastrous because sulfur cross-links reacted with copper conductors, inducing severe signal attenuation. The breakthrough came when telegraph engineers adopted gutta-percha, a natural latex exudate harvested primarily from trees of the genus Palaquium in Southeast Asia. Unlike rubber, gutta-percha consists predominantly of trans-1,4-polyisoprene, a stereoisomer whose linear molecular configuration enables dense crystalline packing at room temperature. This unique structural attribute confers extraordinary chemical inertness, high dielectric strength, and thermoplastic plasticity, allowing the material to be seamlessly extruded around copper wire. Crucially, when submerged in cold ocean waters, gutta-percha undergoes a phase transformation that increases its density and mechanical rigidity, effectively enhancing its insulating efficacy under deep-sea conditions. However, the rapidly surging demand for submarine cable networks precipitated an ecological crisis in the Malayan archipelago. Harvesters routinely felled mature trees rather than employing sustainable tapping techniques, causing widespread deforestation and threatening local populations of Palaquium gutta. To mitigate these supply disruptions, the British East India Company commissioned botanist Thomas Oxley to investigate cultivation methods. Oxley demonstrated that while cultivated trees required nearly three decades to reach harvesting maturity, systematic bark incisions on standing timber could yield sustainable annual harvests without killing the trees. Despite Oxley’s recommendations, commercial cartels continued destructive harvesting practices until synthetic polyolefins eclipsed natural resins in the mid-twentieth century.

According to the passage, the physical behavior of gutta-percha when exposed to deep ocean submerged conditions is explicitly characterized by which of the following?