Reading Comprehension VIP Practice Exam II

Read the following passage and answer the question. "The hadal zone, defined as ocean depths below 6,000 meters, was once believed to be entirely devoid of life. Early oceanographers theorized that the crushing pressure — over 600 times that at sea level — combined with perpetual darkness and near-freezing temperatures would render any biological processes impossible. However, systematic exploration beginning in the 1950s, accelerated by advances in remotely operated vehicles (ROVs) in the 1990s, revealed not merely the presence of life but an astonishing abundance of highly specialized organisms. The snailfish (genus Pseudoliparis), for instance, has been recorded at depths exceeding 8,300 meters in the Mariana Trench, making it the deepest-dwelling vertebrate known to science. What enables snailfish to survive at such depths is partly a molecule called trimethylamine N-oxide (TMAO), which stabilizes cellular proteins under extreme pressure. The presence of such biochemical adaptations has led marine biologists to reconsider fundamental assumptions about the limits of vertebrate physiology, with some researchers suggesting that TMAO concentration may act as a biological 'depth ceiling,' beyond which even highly adapted fish cannot survive — a hypothesis that remains actively debated." The passage is primarily concerned with which of the following?

Questions 2–28 and full explanations are VIP-exclusive.