Text 1
Many paleontologists argue that the prominent neural spine sail of the dinosaur *Spinosaurus* functioned primarily as a thermoregulatory structure. According to this view, the massive sail allowed the creature to absorb or dissipate heat in its semi-aquatic environment. Researchers point to the extensive network of vascular grooves on the fossilized spines as evidence of active blood flow, which would have facilitated rapid heat exchange. Under this hypothesis, the sail was a crucial physiological adaptation for survival in a hot, Cretaceous climate.
Text 2
Conversely, paleontologist Dr. Maya Lin contends that the thermoregulatory hypothesis is biologically implausible. Lin notes that modern semi-aquatic apex predators, such as crocodilians, regulate their body temperatures effectively without specialized dorsal sails. Instead, Lin proposes that the sail served a visual display function, signaling maturity to potential mates and rivals. She argues that the vascular grooves observed in the fossils are merely byproducts of rapid skeletal growth during adolescence, rather than evidence of a dedicated heat-exchange system.
Based on the texts, how would Dr. Lin (Text 2) most likely characterize the 'vascular grooves' cited by the paleontologists in Text 1?
- AAs a physiological feature that confirms the close evolutionary relationship between *Spinosaurus* and modern crocodilians
- BAs a misidentified fossil structure that does not actually exist in *Spinosaurus* specimens
- As a growth-related skeletal feature rather than evidence of a functional heat-dissipation systemCevap
- DAs a specialized sensory mechanism that allowed the dinosaur to navigate semi-aquatic habitats