Upon underwater()by divers,there are no apparent()on the bottom plates of the said vessel.
For hundreds of years, pearl divers have gathered pearls directly from mollusks on the seafloor. This is an extremely risky profession, exposing the divers to risks of drowning, air embolism, and shark attacks. Still, as long as society demands authentic cultured pearls, these brave divers must continue to risk their lives.
Which of the following statements, if true, most seriously weakens the conclusion above?